Thi thử VSTEP online 10 reading test 1 part 2

PASSAGE 3

At the end of the 1800's, Thomas Edison introduced the incandescent light bulb and changed the world. Remarkably, the incandescent bulb used today has changed little in over a hundred years. An incandescent light consists of a glass bulb filled with an inert gas such as argon. Inside the bulb, electricity passes through a metal filament. Because of resistance, the filament becomes so hot that it glows. But 95% of the energy goes to produce heat and is basically wasted. Given that 20% of the world's electricity is used to power lights, this represents an enormous amount of wasted energy.

In the 1940's a new, more efficient form of lighting, the fluorescent bulb, was introduced. Fluorescents work by passing electrical current through gas in a tube, producing invisible ultraviolet light. A phosphor coating on the inside of the tube then converts the ultraviolet to visible light. Little heat is wasted. Fluorescents have proved popular in offices, factories, and stores, but they never took over the residential lighting market. The harsh color isn't as pleasing as the warmer glow of incandescent lamps. Besides, they have a tendency to flicker on and off and to produce an annoying buzz.

Now, lighting engineers are developing a new form of lighting that is both pleasing to the eyes and energy efficient. This is the light-emitting diode, or LED. LEDs are made up of layers of electron-charged substances. When an electrical current passes through the layers, electrons jump from one layer to another and give off light without producing heat. Different types of materials result in light of different colors. Red, green, and orange LEDs have been used for decades in devices such as digital clocks, calculators, and electronic toys. In the future, however, white-light-emitting diodes (WLEDs) may be used to light homes. Engineers say that they are significantly more efficient than either incandescent or fluorescent lights.

The next challenge for researchers is to develop an efficient, bright, inexpensive WLED. A few years ago, a Japanese scientist named Shuji Nakamura discovered that, by using layers of gallium nitride, he could create a powerful blue LED. Later, engineers devised two ways to use this blue LED to create a WLED. Red, green, and blue LEDs can be combined, creating a pleasant white light. Another way is to use a chemical coating similar to that inside a fluorescent bulb that converts the blue light to white. Nevertheless, it will still be some time before WLEDs are commonly used in homes. WLEDs are currently only twice as energy efficient as incandescent. They are also very expensive. But researchers believe that they can create WLEDs that are ten times as efficient and one thousand times as long-lasting as incandescent lights, making them cost effective.

LEDs may someday have an even greater impact on developing countries than in the developed world. Worldwide, an estimated 2 billion people lack access to electricity. Lighting is usually provided by kerosene lamps. Kerosene is expensive, creates indoor pollution, does not provide very bright light, and worst of all, causes many fires. A low-energy (1-watt) WLED can provide enough light for a person to read by – more light, in fact, than most kerosene lamps. An entire rural village could be lighted with less energy than that used by a single conventional 100-watt light bulb. Energy to light these efficient LEDs can be provided by batteries that are charged by pedal-driven generators, by hydroelectricity from rivers or streams, by wind-powered generators, or by solar energy.

PASSAGE 3

At the end of the 1800's, Thomas Edison introduced the incandescent light bulb and changed the world. Remarkably, the incandescent bulb used today has changed little in over a hundred years. An incandescent light consists of a glass bulb filled with an inert gas such as argon. Inside the bulb, electricity passes through a metal filament. Because of resistance, the filament becomes so hot that it glows. But 95% of the energy goes to produce heat and is basically wasted. Given that 20% of the world's electricity is used to power lights, this represents an enormous amount of wasted energy.

In the 1940's a new, more efficient form of lighting, the fluorescent bulb, was introduced. Fluorescents work by passing electrical current through gas in a tube, producing invisible ultraviolet light. A phosphor coating on the inside of the tube then converts the ultraviolet to visible light. Little heat is wasted. Fluorescents have proved popular in offices, factories, and stores, but they never took over the residential lighting market. The harsh color isn't as pleasing as the warmer glow of incandescent lamps. Besides, they have a tendency to flicker on and off and to produce an annoying buzz.

Now, lighting engineers are developing a new form of lighting that is both pleasing to the eyes and energy efficient. This is the light-emitting diode, or LED. LEDs are made up of layers of electron-charged substances. When an electrical current passes through the layers, electrons jump from one layer to another and give off light without producing heat. Different types of materials result in light of different colors. Red, green, and orange LEDs have been used for decades in devices such as digital clocks, calculators, and electronic toys. In the future, however, white-light-emitting diodes (WLEDs) may be used to light homes. Engineers say that they are significantly more efficient than either incandescent or fluorescent lights.

The next challenge for researchers is to develop an efficient, bright, inexpensive WLED. A few years ago, a Japanese scientist named Shuji Nakamura discovered that, by using layers of gallium nitride, he could create a powerful blue LED. Later, engineers devised two ways to use this blue LED to create a WLED. Red, green, and blue LEDs can be combined, creating a pleasant white light. Another way is to use a chemical coating similar to that inside a fluorescent bulb that converts the blue light to white. Nevertheless, it will still be some time before WLEDs are commonly used in homes. WLEDs are currently only twice as energy efficient as incandescent. They are also very expensive. But researchers believe that they can create WLEDs that are ten times as efficient and one thousand times as long-lasting as incandescent lights, making them cost effective.

LEDs may someday have an even greater impact on developing countries than in the developed world. Worldwide, an estimated 2 billion people lack access to electricity. Lighting is usually provided by kerosene lamps. Kerosene is expensive, creates indoor pollution, does not provide very bright light, and worst of all, causes many fires. A low-energy (1-watt) WLED can provide enough light for a person to read by – more light, in fact, than most kerosene lamps. An entire rural village could be lighted with less energy than that used by a single conventional 100-watt light bulb. Energy to light these efficient LEDs can be provided by batteries that are charged by pedal-driven generators, by hydroelectricity from rivers or streams, by wind-powered generators, or by solar energy.

PASSAGE 3

At the end of the 1800's, Thomas Edison introduced the incandescent light bulb and changed the world. Remarkably, the incandescent bulb used today has changed little in over a hundred years. An incandescent light consists of a glass bulb filled with an inert gas such as argon. Inside the bulb, electricity passes through a metal filament. Because of resistance, the filament becomes so hot that it glows. But 95% of the energy goes to produce heat and is basically wasted. Given that 20% of the world's electricity is used to power lights, this represents an enormous amount of wasted energy.

In the 1940's a new, more efficient form of lighting, the fluorescent bulb, was introduced. Fluorescents work by passing electrical current through gas in a tube, producing invisible ultraviolet light. A phosphor coating on the inside of the tube then converts the ultraviolet to visible light. Little heat is wasted. Fluorescents have proved popular in offices, factories, and stores, but they never took over the residential lighting market. The harsh color isn't as pleasing as the warmer glow of incandescent lamps. Besides, they have a tendency to flicker on and off and to produce an annoying buzz.

Now, lighting engineers are developing a new form of lighting that is both pleasing to the eyes and energy efficient. This is the light-emitting diode, or LED. LEDs are made up of layers of electron-charged substances. When an electrical current passes through the layers, electrons jump from one layer to another and give off light without producing heat. Different types of materials result in light of different colors. Red, green, and orange LEDs have been used for decades in devices such as digital clocks, calculators, and electronic toys. In the future, however, white-light-emitting diodes (WLEDs) may be used to light homes. Engineers say that they are significantly more efficient than either incandescent or fluorescent lights.

The next challenge for researchers is to develop an efficient, bright, inexpensive WLED. A few years ago, a Japanese scientist named Shuji Nakamura discovered that, by using layers of gallium nitride, he could create a powerful blue LED. Later, engineers devised two ways to use this blue LED to create a WLED. Red, green, and blue LEDs can be combined, creating a pleasant white light. Another way is to use a chemical coating similar to that inside a fluorescent bulb that converts the blue light to white. Nevertheless, it will still be some time before WLEDs are commonly used in homes. WLEDs are currently only twice as energy efficient as incandescent. They are also very expensive. But researchers believe that they can create WLEDs that are ten times as efficient and one thousand times as long-lasting as incandescent lights, making them cost effective.

LEDs may someday have an even greater impact on developing countries than in the developed world. Worldwide, an estimated 2 billion people lack access to electricity. Lighting is usually provided by kerosene lamps. Kerosene is expensive, creates indoor pollution, does not provide very bright light, and worst of all, causes many fires. A low-energy (1-watt) WLED can provide enough light for a person to read by – more light, in fact, than most kerosene lamps. An entire rural village could be lighted with less energy than that used by a single conventional 100-watt light bulb. Energy to light these efficient LEDs can be provided by batteries that are charged by pedal-driven generators, by hydroelectricity from rivers or streams, by wind-powered generators, or by solar energy.

PASSAGE 3

At the end of the 1800's, Thomas Edison introduced the incandescent light bulb and changed the world. Remarkably, the incandescent bulb used today has changed little in over a hundred years. An incandescent light consists of a glass bulb filled with an inert gas such as argon. Inside the bulb, electricity passes through a metal filament. Because of resistance, the filament becomes so hot that it glows. But 95% of the energy goes to produce heat and is basically wasted. Given that 20% of the world's electricity is used to power lights, this represents an enormous amount of wasted energy.

In the 1940's a new, more efficient form of lighting, the fluorescent bulb, was introduced. Fluorescents work by passing electrical current through gas in a tube, producing invisible ultraviolet light. A phosphor coating on the inside of the tube then converts the ultraviolet to visible light. Little heat is wasted. Fluorescents have proved popular in offices, factories, and stores, but they never took over the residential lighting market. The harsh color isn't as pleasing as the warmer glow of incandescent lamps. Besides, they have a tendency to flicker on and off and to produce an annoying buzz.

Now, lighting engineers are developing a new form of lighting that is both pleasing to the eyes and energy efficient. This is the light-emitting diode, or LED. LEDs are made up of layers of electron-charged substances. When an electrical current passes through the layers, electrons jump from one layer to another and give off light without producing heat. Different types of materials result in light of different colors. Red, green, and orange LEDs have been used for decades in devices such as digital clocks, calculators, and electronic toys. In the future, however, white-light-emitting diodes (WLEDs) may be used to light homes. Engineers say that they are significantly more efficient than either incandescent or fluorescent lights.

The next challenge for researchers is to develop an efficient, bright, inexpensive WLED. A few years ago, a Japanese scientist named Shuji Nakamura discovered that, by using layers of gallium nitride, he could create a powerful blue LED. Later, engineers devised two ways to use this blue LED to create a WLED. Red, green, and blue LEDs can be combined, creating a pleasant white light. Another way is to use a chemical coating similar to that inside a fluorescent bulb that converts the blue light to white. Nevertheless, it will still be some time before WLEDs are commonly used in homes. WLEDs are currently only twice as energy efficient as incandescent. They are also very expensive. But researchers believe that they can create WLEDs that are ten times as efficient and one thousand times as long-lasting as incandescent lights, making them cost effective.

LEDs may someday have an even greater impact on developing countries than in the developed world. Worldwide, an estimated 2 billion people lack access to electricity. Lighting is usually provided by kerosene lamps. Kerosene is expensive, creates indoor pollution, does not provide very bright light, and worst of all, causes many fires. A low-energy (1-watt) WLED can provide enough light for a person to read by – more light, in fact, than most kerosene lamps. An entire rural village could be lighted with less energy than that used by a single conventional 100-watt light bulb. Energy to light these efficient LEDs can be provided by batteries that are charged by pedal-driven generators, by hydroelectricity from rivers or streams, by wind-powered generators, or by solar energy.

PASSAGE 3

At the end of the 1800's, Thomas Edison introduced the incandescent light bulb and changed the world. Remarkably, the incandescent bulb used today has changed little in over a hundred years. An incandescent light consists of a glass bulb filled with an inert gas such as argon. Inside the bulb, electricity passes through a metal filament. Because of resistance, the filament becomes so hot that it glows. But 95% of the energy goes to produce heat and is basically wasted. Given that 20% of the world's electricity is used to power lights, this represents an enormous amount of wasted energy.

In the 1940's a new, more efficient form of lighting, the fluorescent bulb, was introduced. Fluorescents work by passing electrical current through gas in a tube, producing invisible ultraviolet light. A phosphor coating on the inside of the tube then converts the ultraviolet to visible light. Little heat is wasted. Fluorescents have proved popular in offices, factories, and stores, but they never took over the residential lighting market. The harsh color isn't as pleasing as the warmer glow of incandescent lamps. Besides, they have a tendency to flicker on and off and to produce an annoying buzz.

Now, lighting engineers are developing a new form of lighting that is both pleasing to the eyes and energy efficient. This is the light-emitting diode, or LED. LEDs are made up of layers of electron-charged substances. When an electrical current passes through the layers, electrons jump from one layer to another and give off light without producing heat. Different types of materials result in light of different colors. Red, green, and orange LEDs have been used for decades in devices such as digital clocks, calculators, and electronic toys. In the future, however, white-light-emitting diodes (WLEDs) may be used to light homes. Engineers say that they are significantly more efficient than either incandescent or fluorescent lights.

The next challenge for researchers is to develop an efficient, bright, inexpensive WLED. A few years ago, a Japanese scientist named Shuji Nakamura discovered that, by using layers of gallium nitride, he could create a powerful blue LED. Later, engineers devised two ways to use this blue LED to create a WLED. Red, green, and blue LEDs can be combined, creating a pleasant white light. Another way is to use a chemical coating similar to that inside a fluorescent bulb that converts the blue light to white. Nevertheless, it will still be some time before WLEDs are commonly used in homes. WLEDs are currently only twice as energy efficient as incandescent. They are also very expensive. But researchers believe that they can create WLEDs that are ten times as efficient and one thousand times as long-lasting as incandescent lights, making them cost effective.

LEDs may someday have an even greater impact on developing countries than in the developed world. Worldwide, an estimated 2 billion people lack access to electricity. Lighting is usually provided by kerosene lamps. Kerosene is expensive, creates indoor pollution, does not provide very bright light, and worst of all, causes many fires. A low-energy (1-watt) WLED can provide enough light for a person to read by – more light, in fact, than most kerosene lamps. An entire rural village could be lighted with less energy than that used by a single conventional 100-watt light bulb. Energy to light these efficient LEDs can be provided by batteries that are charged by pedal-driven generators, by hydroelectricity from rivers or streams, by wind-powered generators, or by solar energy.

PASSAGE 3

At the end of the 1800's, Thomas Edison introduced the incandescent light bulb and changed the world. Remarkably, the incandescent bulb used today has changed little in over a hundred years. An incandescent light consists of a glass bulb filled with an inert gas such as argon. Inside the bulb, electricity passes through a metal filament. Because of resistance, the filament becomes so hot that it glows. But 95% of the energy goes to produce heat and is basically wasted. Given that 20% of the world's electricity is used to power lights, this represents an enormous amount of wasted energy.

In the 1940's a new, more efficient form of lighting, the fluorescent bulb, was introduced. Fluorescents work by passing electrical current through gas in a tube, producing invisible ultraviolet light. A phosphor coating on the inside of the tube then converts the ultraviolet to visible light. Little heat is wasted. Fluorescents have proved popular in offices, factories, and stores, but they never took over the residential lighting market. The harsh color isn't as pleasing as the warmer glow of incandescent lamps. Besides, they have a tendency to flicker on and off and to produce an annoying buzz.

Now, lighting engineers are developing a new form of lighting that is both pleasing to the eyes and energy efficient. This is the light-emitting diode, or LED. LEDs are made up of layers of electron-charged substances. When an electrical current passes through the layers, electrons jump from one layer to another and give off light without producing heat. Different types of materials result in light of different colors. Red, green, and orange LEDs have been used for decades in devices such as digital clocks, calculators, and electronic toys. In the future, however, white-light-emitting diodes (WLEDs) may be used to light homes. Engineers say that they are significantly more efficient than either incandescent or fluorescent lights.

The next challenge for researchers is to develop an efficient, bright, inexpensive WLED. A few years ago, a Japanese scientist named Shuji Nakamura discovered that, by using layers of gallium nitride, he could create a powerful blue LED. Later, engineers devised two ways to use this blue LED to create a WLED. Red, green, and blue LEDs can be combined, creating a pleasant white light. Another way is to use a chemical coating similar to that inside a fluorescent bulb that converts the blue light to white. Nevertheless, it will still be some time before WLEDs are commonly used in homes. WLEDs are currently only twice as energy efficient as incandescent. They are also very expensive. But researchers believe that they can create WLEDs that are ten times as efficient and one thousand times as long-lasting as incandescent lights, making them cost effective.

LEDs may someday have an even greater impact on developing countries than in the developed world. Worldwide, an estimated 2 billion people lack access to electricity. Lighting is usually provided by kerosene lamps. Kerosene is expensive, creates indoor pollution, does not provide very bright light, and worst of all, causes many fires. A low-energy (1-watt) WLED can provide enough light for a person to read by – more light, in fact, than most kerosene lamps. An entire rural village could be lighted with less energy than that used by a single conventional 100-watt light bulb. Energy to light these efficient LEDs can be provided by batteries that are charged by pedal-driven generators, by hydroelectricity from rivers or streams, by wind-powered generators, or by solar energy.

PASSAGE 3

At the end of the 1800's, Thomas Edison introduced the incandescent light bulb and changed the world. Remarkably, the incandescent bulb used today has changed little in over a hundred years. An incandescent light consists of a glass bulb filled with an inert gas such as argon. Inside the bulb, electricity passes through a metal filament. Because of resistance, the filament becomes so hot that it glows. But 95% of the energy goes to produce heat and is basically wasted. Given that 20% of the world's electricity is used to power lights, this represents an enormous amount of wasted energy.

In the 1940's a new, more efficient form of lighting, the fluorescent bulb, was introduced. Fluorescents work by passing electrical current through gas in a tube, producing invisible ultraviolet light. A phosphor coating on the inside of the tube then converts the ultraviolet to visible light. Little heat is wasted. Fluorescents have proved popular in offices, factories, and stores, but they never took over the residential lighting market. The harsh color isn't as pleasing as the warmer glow of incandescent lamps. Besides, they have a tendency to flicker on and off and to produce an annoying buzz.

Now, lighting engineers are developing a new form of lighting that is both pleasing to the eyes and energy efficient. This is the light-emitting diode, or LED. LEDs are made up of layers of electron-charged substances. When an electrical current passes through the layers, electrons jump from one layer to another and give off light without producing heat. Different types of materials result in light of different colors. Red, green, and orange LEDs have been used for decades in devices such as digital clocks, calculators, and electronic toys. In the future, however, white-light-emitting diodes (WLEDs) may be used to light homes. Engineers say that they are significantly more efficient than either incandescent or fluorescent lights.

The next challenge for researchers is to develop an efficient, bright, inexpensive WLED. A few years ago, a Japanese scientist named Shuji Nakamura discovered that, by using layers of gallium nitride, he could create a powerful blue LED. Later, engineers devised two ways to use this blue LED to create a WLED. Red, green, and blue LEDs can be combined, creating a pleasant white light. Another way is to use a chemical coating similar to that inside a fluorescent bulb that converts the blue light to white. Nevertheless, it will still be some time before WLEDs are commonly used in homes. WLEDs are currently only twice as energy efficient as incandescent. They are also very expensive. But researchers believe that they can create WLEDs that are ten times as efficient and one thousand times as long-lasting as incandescent lights, making them cost effective.

LEDs may someday have an even greater impact on developing countries than in the developed world. Worldwide, an estimated 2 billion people lack access to electricity. Lighting is usually provided by kerosene lamps. Kerosene is expensive, creates indoor pollution, does not provide very bright light, and worst of all, causes many fires. A low-energy (1-watt) WLED can provide enough light for a person to read by – more light, in fact, than most kerosene lamps. An entire rural village could be lighted with less energy than that used by a single conventional 100-watt light bulb. Energy to light these efficient LEDs can be provided by batteries that are charged by pedal-driven generators, by hydroelectricity from rivers or streams, by wind-powered generators, or by solar energy.

PASSAGE 3

At the end of the 1800's, Thomas Edison introduced the incandescent light bulb and changed the world. Remarkably, the incandescent bulb used today has changed little in over a hundred years. An incandescent light consists of a glass bulb filled with an inert gas such as argon. Inside the bulb, electricity passes through a metal filament. Because of resistance, the filament becomes so hot that it glows. But 95% of the energy goes to produce heat and is basically wasted. Given that 20% of the world's electricity is used to power lights, this represents an enormous amount of wasted energy.

In the 1940's a new, more efficient form of lighting, the fluorescent bulb, was introduced. Fluorescents work by passing electrical current through gas in a tube, producing invisible ultraviolet light. A phosphor coating on the inside of the tube then converts the ultraviolet to visible light. Little heat is wasted. Fluorescents have proved popular in offices, factories, and stores, but they never took over the residential lighting market. The harsh color isn't as pleasing as the warmer glow of incandescent lamps. Besides, they have a tendency to flicker on and off and to produce an annoying buzz.

Now, lighting engineers are developing a new form of lighting that is both pleasing to the eyes and energy efficient. This is the light-emitting diode, or LED. LEDs are made up of layers of electron-charged substances. When an electrical current passes through the layers, electrons jump from one layer to another and give off light without producing heat. Different types of materials result in light of different colors. Red, green, and orange LEDs have been used for decades in devices such as digital clocks, calculators, and electronic toys. In the future, however, white-light-emitting diodes (WLEDs) may be used to light homes. Engineers say that they are significantly more efficient than either incandescent or fluorescent lights.

The next challenge for researchers is to develop an efficient, bright, inexpensive WLED. A few years ago, a Japanese scientist named Shuji Nakamura discovered that, by using layers of gallium nitride, he could create a powerful blue LED. Later, engineers devised two ways to use this blue LED to create a WLED. Red, green, and blue LEDs can be combined, creating a pleasant white light. Another way is to use a chemical coating similar to that inside a fluorescent bulb that converts the blue light to white. Nevertheless, it will still be some time before WLEDs are commonly used in homes. WLEDs are currently only twice as energy efficient as incandescent. They are also very expensive. But researchers believe that they can create WLEDs that are ten times as efficient and one thousand times as long-lasting as incandescent lights, making them cost effective.

LEDs may someday have an even greater impact on developing countries than in the developed world. Worldwide, an estimated 2 billion people lack access to electricity. Lighting is usually provided by kerosene lamps. Kerosene is expensive, creates indoor pollution, does not provide very bright light, and worst of all, causes many fires. A low-energy (1-watt) WLED can provide enough light for a person to read by – more light, in fact, than most kerosene lamps. An entire rural village could be lighted with less energy than that used by a single conventional 100-watt light bulb. Energy to light these efficient LEDs can be provided by batteries that are charged by pedal-driven generators, by hydroelectricity from rivers or streams, by wind-powered generators, or by solar energy.

PASSAGE 3

At the end of the 1800's, Thomas Edison introduced the incandescent light bulb and changed the world. Remarkably, the incandescent bulb used today has changed little in over a hundred years. An incandescent light consists of a glass bulb filled with an inert gas such as argon. Inside the bulb, electricity passes through a metal filament. Because of resistance, the filament becomes so hot that it glows. But 95% of the energy goes to produce heat and is basically wasted. Given that 20% of the world's electricity is used to power lights, this represents an enormous amount of wasted energy.

In the 1940's a new, more efficient form of lighting, the fluorescent bulb, was introduced. Fluorescents work by passing electrical current through gas in a tube, producing invisible ultraviolet light. A phosphor coating on the inside of the tube then converts the ultraviolet to visible light. Little heat is wasted. Fluorescents have proved popular in offices, factories, and stores, but they never took over the residential lighting market. The harsh color isn't as pleasing as the warmer glow of incandescent lamps. Besides, they have a tendency to flicker on and off and to produce an annoying buzz.

Now, lighting engineers are developing a new form of lighting that is both pleasing to the eyes and energy efficient. This is the light-emitting diode, or LED. LEDs are made up of layers of electron-charged substances. When an electrical current passes through the layers, electrons jump from one layer to another and give off light without producing heat. Different types of materials result in light of different colors. Red, green, and orange LEDs have been used for decades in devices such as digital clocks, calculators, and electronic toys. In the future, however, white-light-emitting diodes (WLEDs) may be used to light homes. Engineers say that they are significantly more efficient than either incandescent or fluorescent lights.

The next challenge for researchers is to develop an efficient, bright, inexpensive WLED. A few years ago, a Japanese scientist named Shuji Nakamura discovered that, by using layers of gallium nitride, he could create a powerful blue LED. Later, engineers devised two ways to use this blue LED to create a WLED. Red, green, and blue LEDs can be combined, creating a pleasant white light. Another way is to use a chemical coating similar to that inside a fluorescent bulb that converts the blue light to white. Nevertheless, it will still be some time before WLEDs are commonly used in homes. WLEDs are currently only twice as energy efficient as incandescent. They are also very expensive. But researchers believe that they can create WLEDs that are ten times as efficient and one thousand times as long-lasting as incandescent lights, making them cost effective.

LEDs may someday have an even greater impact on developing countries than in the developed world. Worldwide, an estimated 2 billion people lack access to electricity. Lighting is usually provided by kerosene lamps. Kerosene is expensive, creates indoor pollution, does not provide very bright light, and worst of all, causes many fires. A low-energy (1-watt) WLED can provide enough light for a person to read by – more light, in fact, than most kerosene lamps. An entire rural village could be lighted with less energy than that used by a single conventional 100-watt light bulb. Energy to light these efficient LEDs can be provided by batteries that are charged by pedal-driven generators, by hydroelectricity from rivers or streams, by wind-powered generators, or by solar energy.

PASSAGE 3

At the end of the 1800's, Thomas Edison introduced the incandescent light bulb and changed the world. Remarkably, the incandescent bulb used today has changed little in over a hundred years. An incandescent light consists of a glass bulb filled with an inert gas such as argon. Inside the bulb, electricity passes through a metal filament. Because of resistance, the filament becomes so hot that it glows. But 95% of the energy goes to produce heat and is basically wasted. Given that 20% of the world's electricity is used to power lights, this represents an enormous amount of wasted energy.

In the 1940's a new, more efficient form of lighting, the fluorescent bulb, was introduced. Fluorescents work by passing electrical current through gas in a tube, producing invisible ultraviolet light. A phosphor coating on the inside of the tube then converts the ultraviolet to visible light. Little heat is wasted. Fluorescents have proved popular in offices, factories, and stores, but they never took over the residential lighting market. The harsh color isn't as pleasing as the warmer glow of incandescent lamps. Besides, they have a tendency to flicker on and off and to produce an annoying buzz.

Now, lighting engineers are developing a new form of lighting that is both pleasing to the eyes and energy efficient. This is the light-emitting diode, or LED. LEDs are made up of layers of electron-charged substances. When an electrical current passes through the layers, electrons jump from one layer to another and give off light without producing heat. Different types of materials result in light of different colors. Red, green, and orange LEDs have been used for decades in devices such as digital clocks, calculators, and electronic toys. In the future, however, white-light-emitting diodes (WLEDs) may be used to light homes. Engineers say that they are significantly more efficient than either incandescent or fluorescent lights.

The next challenge for researchers is to develop an efficient, bright, inexpensive WLED. A few years ago, a Japanese scientist named Shuji Nakamura discovered that, by using layers of gallium nitride, he could create a powerful blue LED. Later, engineers devised two ways to use this blue LED to create a WLED. Red, green, and blue LEDs can be combined, creating a pleasant white light. Another way is to use a chemical coating similar to that inside a fluorescent bulb that converts the blue light to white. Nevertheless, it will still be some time before WLEDs are commonly used in homes. WLEDs are currently only twice as energy efficient as incandescent. They are also very expensive. But researchers believe that they can create WLEDs that are ten times as efficient and one thousand times as long-lasting as incandescent lights, making them cost effective.

LEDs may someday have an even greater impact on developing countries than in the developed world. Worldwide, an estimated 2 billion people lack access to electricity. Lighting is usually provided by kerosene lamps. Kerosene is expensive, creates indoor pollution, does not provide very bright light, and worst of all, causes many fires. A low-energy (1-watt) WLED can provide enough light for a person to read by – more light, in fact, than most kerosene lamps. An entire rural village could be lighted with less energy than that used by a single conventional 100-watt light bulb. Energy to light these efficient LEDs can be provided by batteries that are charged by pedal-driven generators, by hydroelectricity from rivers or streams, by wind-powered generators, or by solar energy.

PASSAGE 4

An important part of marketing is determining what price to charge consumers for goods and services. Companies aspire to set prices that are high enough to allow them to make a profit but low enough to encourage people to purchase their products. To determine these prices, marketing specialists must consider a variety of factors and use a number of different pricing approaches.

Cost-based approaches determine the price of a product based on how much it costs to make. This is the simplest method because manufacturers can easily determine how much it will cost them to produce their goods. After they calculate the price of materials and labor, they add a set percentage to that cost, called a standard markup, which covers advertising, marketing, and other administrative costs, as well as a profit. The main advantage to this approach is its simplicity. Businesses do not need to adjust their prices constantly based on changes in the market for their goods. However, the inability to account for important factors relating to the market is also the weakness of the cost-based approach. This is why many businesses also use more complex approaches to determine their prices.

In many industries, producers often pay less attention to their own costs and set prices based on those of their leading competitors instead. This is called competition-based pricing. It sometimes puts small businesses at a disadvantage. Because very large companies can buy their materials or production machinery in bulk, they often have lower production costs than smaller companies do. In order to compete, smaller companies cannot depend on cost-based pricing. They often set their prices lower than those of their larger competitors, even though their production costs may be higher, in order to make their products attractive to consumers and build or maintain their customer base.

While cost-based and competition-based pricing are largely based on objective mathematical factors, like production costs and average prices, buyer-based approaches are based on individual perspective. [A] Perceived value is how much consumers feel an item is worth, as opposed to its actual monetary value. [B] For example, a product like a pet rock, which is simply an ordinary rock marketed as a pet, has very little actual monetary value. [C] Marketers will not use production costs to set their price, because this would make the price too low. [D] Instead, they must determine how much consumers feel their product is worth.

Because perceived value is subjective, it is difficult to calculate. One common strategy for determining the perceived value of a product is to interview people in focus groups, small groups of people who share their feelings about a product with market experts. The responses of focus groups often change according to the group being interviewed, so experts try to interview a large enough sample to get useful information. Along with focus groups and market experts, some businesses may even employ psychologists to help them understand the minds and emotions of consumers so that they can create products that people will see as valuable. The more perceived value an item has, the more a company can charge for that item, regardless of its production costs or the prices set by competitors.

PASSAGE 4

An important part of marketing is determining what price to charge consumers for goods and services. Companies aspire to set prices that are high enough to allow them to make a profit but low enough to encourage people to purchase their products. To determine these prices, marketing specialists must consider a variety of factors and use a number of different pricing approaches.

Cost-based approaches determine the price of a product based on how much it costs to make. This is the simplest method because manufacturers can easily determine how much it will cost them to produce their goods. After they calculate the price of materials and labor, they add a set percentage to that cost, called a standard markup, which covers advertising, marketing, and other administrative costs, as well as a profit. The main advantage to this approach is its simplicity. Businesses do not need to adjust their prices constantly based on changes in the market for their goods. However, the inability to account for important factors relating to the market is also the weakness of the cost-based approach. This is why many businesses also use more complex approaches to determine their prices.

In many industries, producers often pay less attention to their own costs and set prices based on those of their leading competitors instead. This is called competition-based pricing. It sometimes puts small businesses at a disadvantage. Because very large companies can buy their materials or production machinery in bulk, they often have lower production costs than smaller companies do. In order to compete, smaller companies cannot depend on cost-based pricing. They often set their prices lower than those of their larger competitors, even though their production costs may be higher, in order to make their products attractive to consumers and build or maintain their customer base.

While cost-based and competition-based pricing are largely based on objective mathematical factors, like production costs and average prices, buyer-based approaches are based on individual perspective. [A] Perceived value is how much consumers feel an item is worth, as opposed to its actual monetary value. [B] For example, a product like a pet rock, which is simply an ordinary rock marketed as a pet, has very little actual monetary value. [C] Marketers will not use production costs to set their price, because this would make the price too low. [D] Instead, they must determine how much consumers feel their product is worth.

Because perceived value is subjective, it is difficult to calculate. One common strategy for determining the perceived value of a product is to interview people in focus groups, small groups of people who share their feelings about a product with market experts. The responses of focus groups often change according to the group being interviewed, so experts try to interview a large enough sample to get useful information. Along with focus groups and market experts, some businesses may even employ psychologists to help them understand the minds and emotions of consumers so that they can create products that people will see as valuable. The more perceived value an item has, the more a company can charge for that item, regardless of its production costs or the prices set by competitors.

PASSAGE 4

An important part of marketing is determining what price to charge consumers for goods and services. Companies aspire to set prices that are high enough to allow them to make a profit but low enough to encourage people to purchase their products. To determine these prices, marketing specialists must consider a variety of factors and use a number of different pricing approaches.

Cost-based approaches determine the price of a product based on how much it costs to make. This is the simplest method because manufacturers can easily determine how much it will cost them to produce their goods. After they calculate the price of materials and labor, they add a set percentage to that cost, called a standard markup, which covers advertising, marketing, and other administrative costs, as well as a profit. The main advantage to this approach is its simplicity. Businesses do not need to adjust their prices constantly based on changes in the market for their goods. However, the inability to account for important factors relating to the market is also the weakness of the cost-based approach. This is why many businesses also use more complex approaches to determine their prices.

In many industries, producers often pay less attention to their own costs and set prices based on those of their leading competitors instead. This is called competition-based pricing. It sometimes puts small businesses at a disadvantage. Because very large companies can buy their materials or production machinery in bulk, they often have lower production costs than smaller companies do. In order to compete, smaller companies cannot depend on cost-based pricing. They often set their prices lower than those of their larger competitors, even though their production costs may be higher, in order to make their products attractive to consumers and build or maintain their customer base.

While cost-based and competition-based pricing are largely based on objective mathematical factors, like production costs and average prices, buyer-based approaches are based on individual perspective. [A] Perceived value is how much consumers feel an item is worth, as opposed to its actual monetary value. [B] For example, a product like a pet rock, which is simply an ordinary rock marketed as a pet, has very little actual monetary value. [C] Marketers will not use production costs to set their price, because this would make the price too low. [D] Instead, they must determine how much consumers feel their product is worth.

Because perceived value is subjective, it is difficult to calculate. One common strategy for determining the perceived value of a product is to interview people in focus groups, small groups of people who share their feelings about a product with market experts. The responses of focus groups often change according to the group being interviewed, so experts try to interview a large enough sample to get useful information. Along with focus groups and market experts, some businesses may even employ psychologists to help them understand the minds and emotions of consumers so that they can create products that people will see as valuable. The more perceived value an item has, the more a company can charge for that item, regardless of its production costs or the prices set by competitors.

PASSAGE 4

An important part of marketing is determining what price to charge consumers for goods and services. Companies aspire to set prices that are high enough to allow them to make a profit but low enough to encourage people to purchase their products. To determine these prices, marketing specialists must consider a variety of factors and use a number of different pricing approaches.

Cost-based approaches determine the price of a product based on how much it costs to make. This is the simplest method because manufacturers can easily determine how much it will cost them to produce their goods. After they calculate the price of materials and labor, they add a set percentage to that cost, called a standard markup, which covers advertising, marketing, and other administrative costs, as well as a profit. The main advantage to this approach is its simplicity. Businesses do not need to adjust their prices constantly based on changes in the market for their goods. However, the inability to account for important factors relating to the market is also the weakness of the cost-based approach. This is why many businesses also use more complex approaches to determine their prices.

In many industries, producers often pay less attention to their own costs and set prices based on those of their leading competitors instead. This is called competition-based pricing. It sometimes puts small businesses at a disadvantage. Because very large companies can buy their materials or production machinery in bulk, they often have lower production costs than smaller companies do. In order to compete, smaller companies cannot depend on cost-based pricing. They often set their prices lower than those of their larger competitors, even though their production costs may be higher, in order to make their products attractive to consumers and build or maintain their customer base.

While cost-based and competition-based pricing are largely based on objective mathematical factors, like production costs and average prices, buyer-based approaches are based on individual perspective. [A] Perceived value is how much consumers feel an item is worth, as opposed to its actual monetary value. [B] For example, a product like a pet rock, which is simply an ordinary rock marketed as a pet, has very little actual monetary value. [C] Marketers will not use production costs to set their price, because this would make the price too low. [D] Instead, they must determine how much consumers feel their product is worth.

Because perceived value is subjective, it is difficult to calculate. One common strategy for determining the perceived value of a product is to interview people in focus groups, small groups of people who share their feelings about a product with market experts. The responses of focus groups often change according to the group being interviewed, so experts try to interview a large enough sample to get useful information. Along with focus groups and market experts, some businesses may even employ psychologists to help them understand the minds and emotions of consumers so that they can create products that people will see as valuable. The more perceived value an item has, the more a company can charge for that item, regardless of its production costs or the prices set by competitors.

PASSAGE 4

An important part of marketing is determining what price to charge consumers for goods and services. Companies aspire to set prices that are high enough to allow them to make a profit but low enough to encourage people to purchase their products. To determine these prices, marketing specialists must consider a variety of factors and use a number of different pricing approaches.

Cost-based approaches determine the price of a product based on how much it costs to make. This is the simplest method because manufacturers can easily determine how much it will cost them to produce their goods. After they calculate the price of materials and labor, they add a set percentage to that cost, called a standard markup, which covers advertising, marketing, and other administrative costs, as well as a profit. The main advantage to this approach is its simplicity. Businesses do not need to adjust their prices constantly based on changes in the market for their goods. However, the inability to account for important factors relating to the market is also the weakness of the cost-based approach. This is why many businesses also use more complex approaches to determine their prices.

In many industries, producers often pay less attention to their own costs and set prices based on those of their leading competitors instead. This is called competition-based pricing. It sometimes puts small businesses at a disadvantage. Because very large companies can buy their materials or production machinery in bulk, they often have lower production costs than smaller companies do. In order to compete, smaller companies cannot depend on cost-based pricing. They often set their prices lower than those of their larger competitors, even though their production costs may be higher, in order to make their products attractive to consumers and build or maintain their customer base.

While cost-based and competition-based pricing are largely based on objective mathematical factors, like production costs and average prices, buyer-based approaches are based on individual perspective. [A] Perceived value is how much consumers feel an item is worth, as opposed to its actual monetary value. [B] For example, a product like a pet rock, which is simply an ordinary rock marketed as a pet, has very little actual monetary value. [C] Marketers will not use production costs to set their price, because this would make the price too low. [D] Instead, they must determine how much consumers feel their product is worth.

Because perceived value is subjective, it is difficult to calculate. One common strategy for determining the perceived value of a product is to interview people in focus groups, small groups of people who share their feelings about a product with market experts. The responses of focus groups often change according to the group being interviewed, so experts try to interview a large enough sample to get useful information. Along with focus groups and market experts, some businesses may even employ psychologists to help them understand the minds and emotions of consumers so that they can create products that people will see as valuable. The more perceived value an item has, the more a company can charge for that item, regardless of its production costs or the prices set by competitors.

PASSAGE 4

An important part of marketing is determining what price to charge consumers for goods and services. Companies aspire to set prices that are high enough to allow them to make a profit but low enough to encourage people to purchase their products. To determine these prices, marketing specialists must consider a variety of factors and use a number of different pricing approaches.

Cost-based approaches determine the price of a product based on how much it costs to make. This is the simplest method because manufacturers can easily determine how much it will cost them to produce their goods. After they calculate the price of materials and labor, they add a set percentage to that cost, called a standard markup, which covers advertising, marketing, and other administrative costs, as well as a profit. The main advantage to this approach is its simplicity. Businesses do not need to adjust their prices constantly based on changes in the market for their goods. However, the inability to account for important factors relating to the market is also the weakness of the cost-based approach. This is why many businesses also use more complex approaches to determine their prices.

In many industries, producers often pay less attention to their own costs and set prices based on those of their leading competitors instead. This is called competition-based pricing. It sometimes puts small businesses at a disadvantage. Because very large companies can buy their materials or production machinery in bulk, they often have lower production costs than smaller companies do. In order to compete, smaller companies cannot depend on cost-based pricing. They often set their prices lower than those of their larger competitors, even though their production costs may be higher, in order to make their products attractive to consumers and build or maintain their customer base.

While cost-based and competition-based pricing are largely based on objective mathematical factors, like production costs and average prices, buyer-based approaches are based on individual perspective. [A] Perceived value is how much consumers feel an item is worth, as opposed to its actual monetary value. [B] For example, a product like a pet rock, which is simply an ordinary rock marketed as a pet, has very little actual monetary value. [C] Marketers will not use production costs to set their price, because this would make the price too low. [D] Instead, they must determine how much consumers feel their product is worth.

Because perceived value is subjective, it is difficult to calculate. One common strategy for determining the perceived value of a product is to interview people in focus groups, small groups of people who share their feelings about a product with market experts. The responses of focus groups often change according to the group being interviewed, so experts try to interview a large enough sample to get useful information. Along with focus groups and market experts, some businesses may even employ psychologists to help them understand the minds and emotions of consumers so that they can create products that people will see as valuable. The more perceived value an item has, the more a company can charge for that item, regardless of its production costs or the prices set by competitors.

PASSAGE 4

An important part of marketing is determining what price to charge consumers for goods and services. Companies aspire to set prices that are high enough to allow them to make a profit but low enough to encourage people to purchase their products. To determine these prices, marketing specialists must consider a variety of factors and use a number of different pricing approaches.

Cost-based approaches determine the price of a product based on how much it costs to make. This is the simplest method because manufacturers can easily determine how much it will cost them to produce their goods. After they calculate the price of materials and labor, they add a set percentage to that cost, called a standard markup, which covers advertising, marketing, and other administrative costs, as well as a profit. The main advantage to this approach is its simplicity. Businesses do not need to adjust their prices constantly based on changes in the market for their goods. However, the inability to account for important factors relating to the market is also the weakness of the cost-based approach. This is why many businesses also use more complex approaches to determine their prices.

In many industries, producers often pay less attention to their own costs and set prices based on those of their leading competitors instead. This is called competition-based pricing. It sometimes puts small businesses at a disadvantage. Because very large companies can buy their materials or production machinery in bulk, they often have lower production costs than smaller companies do. In order to compete, smaller companies cannot depend on cost-based pricing. They often set their prices lower than those of their larger competitors, even though their production costs may be higher, in order to make their products attractive to consumers and build or maintain their customer base.

While cost-based and competition-based pricing are largely based on objective mathematical factors, like production costs and average prices, buyer-based approaches are based on individual perspective. [A] Perceived value is how much consumers feel an item is worth, as opposed to its actual monetary value. [B] For example, a product like a pet rock, which is simply an ordinary rock marketed as a pet, has very little actual monetary value. [C] Marketers will not use production costs to set their price, because this would make the price too low. [D] Instead, they must determine how much consumers feel their product is worth.

Because perceived value is subjective, it is difficult to calculate. One common strategy for determining the perceived value of a product is to interview people in focus groups, small groups of people who share their feelings about a product with market experts. The responses of focus groups often change according to the group being interviewed, so experts try to interview a large enough sample to get useful information. Along with focus groups and market experts, some businesses may even employ psychologists to help them understand the minds and emotions of consumers so that they can create products that people will see as valuable. The more perceived value an item has, the more a company can charge for that item, regardless of its production costs or the prices set by competitors.

PASSAGE 4

An important part of marketing is determining what price to charge consumers for goods and services. Companies aspire to set prices that are high enough to allow them to make a profit but low enough to encourage people to purchase their products. To determine these prices, marketing specialists must consider a variety of factors and use a number of different pricing approaches.

Cost-based approaches determine the price of a product based on how much it costs to make. This is the simplest method because manufacturers can easily determine how much it will cost them to produce their goods. After they calculate the price of materials and labor, they add a set percentage to that cost, called a standard markup, which covers advertising, marketing, and other administrative costs, as well as a profit. The main advantage to this approach is its simplicity. Businesses do not need to adjust their prices constantly based on changes in the market for their goods. However, the inability to account for important factors relating to the market is also the weakness of the cost-based approach. This is why many businesses also use more complex approaches to determine their prices.

In many industries, producers often pay less attention to their own costs and set prices based on those of their leading competitors instead. This is called competition-based pricing. It sometimes puts small businesses at a disadvantage. Because very large companies can buy their materials or production machinery in bulk, they often have lower production costs than smaller companies do. In order to compete, smaller companies cannot depend on cost-based pricing. They often set their prices lower than those of their larger competitors, even though their production costs may be higher, in order to make their products attractive to consumers and build or maintain their customer base.

While cost-based and competition-based pricing are largely based on objective mathematical factors, like production costs and average prices, buyer-based approaches are based on individual perspective. [A] Perceived value is how much consumers feel an item is worth, as opposed to its actual monetary value. [B] For example, a product like a pet rock, which is simply an ordinary rock marketed as a pet, has very little actual monetary value. [C] Marketers will not use production costs to set their price, because this would make the price too low. [D] Instead, they must determine how much consumers feel their product is worth.

Because perceived value is subjective, it is difficult to calculate. One common strategy for determining the perceived value of a product is to interview people in focus groups, small groups of people who share their feelings about a product with market experts. The responses of focus groups often change according to the group being interviewed, so experts try to interview a large enough sample to get useful information. Along with focus groups and market experts, some businesses may even employ psychologists to help them understand the minds and emotions of consumers so that they can create products that people will see as valuable. The more perceived value an item has, the more a company can charge for that item, regardless of its production costs or the prices set by competitors.

PASSAGE 4

An important part of marketing is determining what price to charge consumers for goods and services. Companies aspire to set prices that are high enough to allow them to make a profit but low enough to encourage people to purchase their products. To determine these prices, marketing specialists must consider a variety of factors and use a number of different pricing approaches.

Cost-based approaches determine the price of a product based on how much it costs to make. This is the simplest method because manufacturers can easily determine how much it will cost them to produce their goods. After they calculate the price of materials and labor, they add a set percentage to that cost, called a standard markup, which covers advertising, marketing, and other administrative costs, as well as a profit. The main advantage to this approach is its simplicity. Businesses do not need to adjust their prices constantly based on changes in the market for their goods. However, the inability to account for important factors relating to the market is also the weakness of the cost-based approach. This is why many businesses also use more complex approaches to determine their prices.

In many industries, producers often pay less attention to their own costs and set prices based on those of their leading competitors instead. This is called competition-based pricing. It sometimes puts small businesses at a disadvantage. Because very large companies can buy their materials or production machinery in bulk, they often have lower production costs than smaller companies do. In order to compete, smaller companies cannot depend on cost-based pricing. They often set their prices lower than those of their larger competitors, even though their production costs may be higher, in order to make their products attractive to consumers and build or maintain their customer base.

While cost-based and competition-based pricing are largely based on objective mathematical factors, like production costs and average prices, buyer-based approaches are based on individual perspective. [A] Perceived value is how much consumers feel an item is worth, as opposed to its actual monetary value. [B] For example, a product like a pet rock, which is simply an ordinary rock marketed as a pet, has very little actual monetary value. [C] Marketers will not use production costs to set their price, because this would make the price too low. [D] Instead, they must determine how much consumers feel their product is worth.

Because perceived value is subjective, it is difficult to calculate. One common strategy for determining the perceived value of a product is to interview people in focus groups, small groups of people who share their feelings about a product with market experts. The responses of focus groups often change according to the group being interviewed, so experts try to interview a large enough sample to get useful information. Along with focus groups and market experts, some businesses may even employ psychologists to help them understand the minds and emotions of consumers so that they can create products that people will see as valuable. The more perceived value an item has, the more a company can charge for that item, regardless of its production costs or the prices set by competitors.

PASSAGE 4

An important part of marketing is determining what price to charge consumers for goods and services. Companies aspire to set prices that are high enough to allow them to make a profit but low enough to encourage people to purchase their products. To determine these prices, marketing specialists must consider a variety of factors and use a number of different pricing approaches.

Cost-based approaches determine the price of a product based on how much it costs to make. This is the simplest method because manufacturers can easily determine how much it will cost them to produce their goods. After they calculate the price of materials and labor, they add a set percentage to that cost, called a standard markup, which covers advertising, marketing, and other administrative costs, as well as a profit. The main advantage to this approach is its simplicity. Businesses do not need to adjust their prices constantly based on changes in the market for their goods. However, the inability to account for important factors relating to the market is also the weakness of the cost-based approach. This is why many businesses also use more complex approaches to determine their prices.

In many industries, producers often pay less attention to their own costs and set prices based on those of their leading competitors instead. This is called competition-based pricing. It sometimes puts small businesses at a disadvantage. Because very large companies can buy their materials or production machinery in bulk, they often have lower production costs than smaller companies do. In order to compete, smaller companies cannot depend on cost-based pricing. They often set their prices lower than those of their larger competitors, even though their production costs may be higher, in order to make their products attractive to consumers and build or maintain their customer base.

While cost-based and competition-based pricing are largely based on objective mathematical factors, like production costs and average prices, buyer-based approaches are based on individual perspective. [A] Perceived value is how much consumers feel an item is worth, as opposed to its actual monetary value. [B] For example, a product like a pet rock, which is simply an ordinary rock marketed as a pet, has very little actual monetary value. [C] Marketers will not use production costs to set their price, because this would make the price too low. [D] Instead, they must determine how much consumers feel their product is worth.

Because perceived value is subjective, it is difficult to calculate. One common strategy for determining the perceived value of a product is to interview people in focus groups, small groups of people who share their feelings about a product with market experts. The responses of focus groups often change according to the group being interviewed, so experts try to interview a large enough sample to get useful information. Along with focus groups and market experts, some businesses may even employ psychologists to help them understand the minds and emotions of consumers so that they can create products that people will see as valuable. The more perceived value an item has, the more a company can charge for that item, regardless of its production costs or the prices set by competitors.