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example of electromagnetic radiation | (A) speed of light (B) wavelength (C) wave frequency (D) wave speed (E) light (F) medium | E | The most important source of electromagnetic radiation on Earth is the sun. Electromagnetic waves travel from the sun to Earth across space and provide virtually all the energy that supports life on our planet. Many other sources of electromagnetic waves that people use depend on technology. Radio waves, microwaves, an... |
value that equals wavelength multiplied by wave frequency | (A) speed of light (B) wavelength (C) wave frequency (D) wave speed (E) light (F) medium | D | The equation for wave speed (above) can be rewritten as: Frequency = Speed Wavelength or Wavelength = Speed Frequency Therefore, if you know the speed of a wave and either the wavelength or wave frequency, you can calculate the missing value. For example, suppose that a wave is traveling at a speed of 2 meters per seco... |
Properties of electromagnetic waves include | (A) speed (B) wavelength (C) frequency (D) all of the above | D | Wavelength and frequency are defined in the same way for electromagnetic waves as they are for mechanical waves. Both properties are illustrated in Figure 21.5. Wavelength is the distance between corresponding points of adjacent waves. Wavelengths of electromagnetic waves range from many kilometers to a tiny fraction o... |
Light slows down when it | (A) travels across space (B) passes from air to water (C) passes from water to air (D) two of the above | B | Although the speed of light is constant in a vacuum, light travels at different speeds in different kinds of matter. For example, light travels more slowly in glass than in air. Therefore, when light passes from air to glass, it slows down. If light strikes a sheet of glass straight on, or perpendicular to the glass, i... |
Electromagnetic waves may vary in their | (A) speed across space (B) energy level (C) frequency (D) two of the above | D | Although all electromagnetic waves travel at the same speed, they may differ in their wavelength and frequency. |
Wavelengths of electromagnetic waves range from | (A) many kilometers to a tiny fraction of a millimeter (B) millions of kilometers to several meters (C) several meters to a few millimeters (D) one kilometer to one millimeter | A | Mid-wavelength electromagnetic waves are commonly called light. This range of electromagnetic waves has shorter wavelengths and higher frequencies than radio waves, but not as short and high as X rays and gamma rays. Light includes visible light, infrared light, and ultraviolet light. If you look back at Figure 21.7, y... |
The highest-frequency electromagnetic waves have a frequency of | (A) hundreds of waves per second (B) thousands of waves per second (C) millions of waves per second (D) trillions of waves per second | D | As you can see in the Figure 1.1, gamma rays have the shortest wavelengths and highest frequencies of all electromagnetic waves. Their wavelengths are shorter than the diameter of atomic nuclei, and their frequencies are greater than 1019 hertz (Hz). Thats 10 quadrillion waves per second! Because of their high frequenc... |
If the wavelength of an electromagnetic wave is 3.0 m, what is its frequency? | (A) 90 102 hertz (B) 60 104 hertz (C) 30 106 hertz (D) 10 108 hertz | D | The speed of a wave is a product of its wavelength and frequency. Because all electromagnetic waves travel at the same speed through space, a wave with a shorter wavelength must have a higher frequency, and vice versa. This relationship is represented by the equation: Speed = Wavelength Frequency The equation for wave... |
If the frequency of an electromagnetic wave is 3.0 108 hertz, what is its wavelength? | (A) 1 mm (B) 1 cm (C) 1m (D) 1 km | C | The speed of a wave is a product of its wavelength and frequency. Because all electromagnetic waves travel at the same speed through space, a wave with a shorter wavelength must have a higher frequency, and vice versa. This relationship is represented by the equation: Speed = Wavelength Frequency The equation for wave... |
Radio waves have the least amount of energy of all electromagnetic waves. | (A) true (B) false | A | Radio waves are the broad range of electromagnetic waves with the longest wavelengths and lowest frequencies. In Figure 21.7, you can see that the wavelength of radio waves may be longer than a soccer field. With their low frequencies, radio waves have the least energy of electromagnetic waves, but they still are extre... |
Which electromagnetic waves are used for cell phone signals? | (A) X rays (B) microwaves (C) gamma rays (D) none of the above | B | Cell phone signals are carried through the air as microwaves. You can see how this works in the Figure 1.2. A cell phone encodes the sounds of the callers voice in microwaves by changing the frequency of the waves. This is called frequency modulation. The encoded microwaves are then sent from the phone through the air ... |
Visible light has higher-frequency waves than ultraviolet light. | (A) true (B) false | B | Light includes infrared light, visible light, and ultraviolet light. As you can see from the Figure 1.1, light falls roughly in the middle of the electromagnetic spectrum. It has shorter wavelengths and higher frequencies than microwaves, but not as short and high as X rays. Q: Which type of light do you think is harmf... |
Which choice lists electromagnetic waves in the correct sequence from higher to lower frequencies? | (A) microwaves (B) infrared light (C) visible light (D) b ultraviolet light (E) X rays (F) gamma rays (G) c X rays (H) ultraviolet light (I) visible light (J) d radio waves (K) microwaves (L) infrared light | C | Electromagnetic waves on the left side of the Figure 1.1 are called radio waves. Radio waves are electromagnetic waves with the longest wavelengths. They may have wavelengths longer than a soccer field. They are also the electromagnetic waves with the lowest frequencies. With their low frequencies, they have the least ... |
Cell phone transmissions are carried by microwaves. | (A) true (B) false | A | Cell phone signals are carried through the air as microwaves. You can see how this works in the Figure 1.2. A cell phone encodes the sounds of the callers voice in microwaves by changing the frequency of the waves. This is called frequency modulation. The encoded microwaves are then sent from the phone through the air ... |
Electromagnetic waves that have the least amount of energy are | (A) radio waves (B) infrared light (C) visible light (D) ultraviolet light | A | The shortest-wavelength, highest-frequency electromagnetic waves are X rays and gamma rays. These rays have so much energy that they can pass through many materials. This makes them potentially very harmful, but it also makes them useful for certain purposes. |
What color does the shortest wavelength of visible light appear to the human eye? | (A) red (B) yellow (C) orange (D) violet | D | Visible light is light that has wavelengths that can be detected by the human eye. The wavelength of visible light determines the color that the light appears. As you can see in the Figure 1.1, light with the longest wavelength appears red, and light with the shortest wavelength appears violet. In between are all the o... |
Radar stands for radio detection and recovery. | (A) true (B) false | B | Radar stands for Radio Detection and Ranging (Figure 1.2). A transmitter sends out radio waves that bounce off the nearest object and then return to a receiver. Weather radar can sense many characteristics of precipitation: its location, motion, intensity, and the likelihood of future precipitation. Doppler radar can a... |
Visible light consists of a very wide range of wavelengths. | (A) true (B) false | B | Visible light consists of a range of wavelengths. The wavelength of visible light determines the color that the light appears. As you can see in Figure 22.4, light with the longest wavelength appears red, and light with the shortest wavelength appears violet. In between is a continuum of all the other colors of light. ... |
X rays are used for | (A) tracking storms (B) killing bacteria (C) screening luggage at airports (D) two of the above | C | X rays are high-energy electromagnetic waves. They have enough energy to pass through soft tissues such as skin but not enough to pass through bones and teeth, which are very dense. The bright areas on the X ray film in Figure also to screen luggage at airports (see Figure 21.14). Too much X ray exposure may cause canc... |
You should protect your skin from ultraviolet light even on cloudy days. | (A) true (B) false | A | Light with wavelengths shorter than visible light is called ultraviolet light. The term ultraviolet means above violet. Ultraviolet light is the range of light waves that have shorter wavelengths and higher frequencies than violet light in the visible range of light. With higher frequencies than visible light, ultravio... |
The only use of X rays is to make images of bones and teeth inside the body. | (A) true (B) false | B | X rays are high-energy electromagnetic waves. They have enough energy to pass through soft tissues such as skin but not enough to pass through bones and teeth, which are very dense. The bright areas on the X ray film in Figure also to screen luggage at airports (see Figure 21.14). Too much X ray exposure may cause canc... |
Gamma rays cannot pass through bones and teeth. | (A) true (B) false | B | Gamma rays are the most energetic of all electromagnetic waves. They can pass through most materials, including bones and teeth. Nonetheless, even these waves are useful. For example, they can be used to treat cancer. A medical device sends gamma rays the site of the cancer, and the rays destroy the cancerous cells. If... |
Gamma rays can be used to destroy cancer cells. | (A) true (B) false | A | The extremely high energy of gamma rays allows them to penetrate just about anything. They can even pass through bones and teeth. This makes gamma rays very dangerous. They can destroy living cells, produce gene mutations, and cause cancer. Ironically, the deadly effects of gamma rays can be used to treat cancer. In th... |
Radar is used for tracking storms. | (A) true (B) false | A | Radar stands for Radio Detection and Ranging (Figure 1.2). A transmitter sends out radio waves that bounce off the nearest object and then return to a receiver. Weather radar can sense many characteristics of precipitation: its location, motion, intensity, and the likelihood of future precipitation. Doppler radar can a... |
Ultraviolet light has shorter wavelengths than visible light. | (A) true (B) false | A | Light with wavelengths shorter than visible light is called ultraviolet light. The term ultraviolet means "above violet." Ultraviolet light is the range of light waves that have shorter wavelengths than violet light in the visible spectrum. Humans cant see ultraviolet light, but it is very useful nonetheless. It has hi... |
Which of the following choices lists electromagnetic waves from lower to higher frequencies? | (A) radio waves (B) infrared light (C) microwaves (D) b ultraviolet light (E) infrared light (F) X rays (G) c infrared light (H) ultraviolet light (I) gamma rays (J) d visible light (K) microwaves (L) ultraviolet light | C | Electromagnetic waves on the left side of the Figure 1.1 are called radio waves. Radio waves are electromagnetic waves with the longest wavelengths. They may have wavelengths longer than a soccer field. They are also the electromagnetic waves with the lowest frequencies. With their low frequencies, they have the least ... |
Television broadcasts cannot pass through the ionosphere. | (A) true (B) false | B | Within the thermosphere is the ionosphere. The ionosphere gets its name from the solar radiation that ionizes gas molecules to create a positively charged ion and one or more negatively charged electrons. The freed electrons travel within the ionosphere as electric currents. Because of the free ions, the ionosphere has... |
Which electromagnetic waves have a wavelength about as wide as the nucleus of an atom? | (A) radio waves (B) infrared light (C) ultraviolet light (D) gamma rays | D | As you can see in the Figure 1.1, gamma rays have the shortest wavelengths and highest frequencies of all electromagnetic waves. Their wavelengths are shorter than the diameter of atomic nuclei, and their frequencies are greater than 1019 hertz (Hz). Thats 10 quadrillion waves per second! Because of their high frequenc... |
Compared with FM radio broadcasts, AM radio broadcasts can | (A) carry more information (B) be heard more clearly (C) pass through the ionosphere (D) travel to more distant receivers | D | In radio broadcasts, sounds are encoded in radio waves that are sent out through the atmosphere from a radio tower. A receiver detects the radio waves and changes them back to sounds. Youve probably listened to both AM and FM radio stations. How sounds are encoded in radio waves differs between AM and FM broadcasts. AM... |
Television broadcasts encode pictures with amplitude modulation. | (A) true (B) false | A | Television broadcasts also use radio waves (see Figure 1.2). For TV broadcasts, sounds are encoded with frequency modulation, and pictures are encoded with amplitude modulation. The encoded waves are broadcast from a TV tower. When the waves are received by television sets, they are decoded and changed back to sounds a... |
Television broadcasts encode pictures by changing the | (A) frequency of radio waves (B) amplitude of radio waves (C) wavelength of radio waves (D) speed of radio waves | B | Television broadcasts also use radio waves. Sounds are encoded with frequency modulation, and pictures are encoded with amplitude modulation. The encoded radio waves are broadcast from a TV tower like the one in Figure 21.9. When the waves are received by television sets, they are decoded and changed back to sounds and... |
Infrared light is used to sterilize surgical instruments. | (A) true (B) false | B | Mirrors and lenses are used in optical instruments to reflect and refract light. Optical instruments include micro- scopes, telescopes, cameras, and lasers. |
X rays cannot pass through lead. | (A) true (B) false | A | X rays are high-energy electromagnetic waves. They have enough energy to pass through soft tissues such as skin but not enough to pass through bones and teeth, which are very dense. The bright areas on the X ray film in Figure also to screen luggage at airports (see Figure 21.14). Too much X ray exposure may cause canc... |
Which type of electromagnetic waves are used for radar? | (A) ultraviolet waves (B) radar waves (C) microwaves (D) X rays | C | Electromagnetic waves carry energy through matter or space as vibrating electric and magnetic fields. Electromag- netic waves have a wide range of wavelengths and frequencies. The complete range is called the electromagnetic spectrum. The Figure 1.1 shows all the waves of the spectrum. The waves used in radar guns are ... |
Visible light with the longest wavelength appears to be | (A) violet (B) green (C) blue (D) red | D | Visible light is light that has wavelengths that can be detected by the human eye. The wavelength of visible light determines the color that the light appears. As you can see in the Figure 1.1, light with the longest wavelength appears red, and light with the shortest wavelength appears violet. In between are all the o... |
Uses of ultraviolet light include | (A) killing bacteria (B) sterilizing surgical instruments (C) making vitamin D by the skin (D) all of the above | D | Light with wavelengths shorter than visible light is called ultraviolet light. The term ultraviolet means above violet. Ultraviolet light is the range of light waves that have shorter wavelengths and higher frequencies than violet light in the visible range of light. With higher frequencies than visible light, ultravio... |
electromagnetic waves with the greatest energy | (A) radio waves (B) infrared light (C) ultraviolet light (D) microwaves (E) electromagnetic spectrum (F) visible light (G) gamma rays | G | As you can see in the Figure 1.1, gamma rays have the shortest wavelengths and highest frequencies of all electromagnetic waves. Their wavelengths are shorter than the diameter of atomic nuclei, and their frequencies are greater than 1019 hertz (Hz). Thats 10 quadrillion waves per second! Because of their high frequenc... |
full range of wavelengths of electromagnetic radiation | (A) radio waves (B) infrared light (C) ultraviolet light (D) microwaves (E) electromagnetic spectrum (F) visible light (G) gamma rays | E | Electromagnetic radiation occurs in waves of different wavelengths and frequencies. Infrared light and visible light make up just a small part of the full range of electromagnetic radiation, which is called the electromagnetic spectrum. The electromagnetic spectrum is summarized in the diagram in Figure 21.7. On the fa... |
electromagnetic waves with wavelengths between infrared and ultraviolet light | (A) radio waves (B) infrared light (C) ultraviolet light (D) microwaves (E) electromagnetic spectrum (F) visible light (G) gamma rays | F | Mid-wavelength electromagnetic waves are commonly called light. This range of electromagnetic waves has shorter wavelengths and higher frequencies than radio waves, but not as short and high as X rays and gamma rays. Light includes visible light, infrared light, and ultraviolet light. If you look back at Figure 21.7, y... |
light with the shortest wavelengths | (A) radio waves (B) infrared light (C) ultraviolet light (D) microwaves (E) electromagnetic spectrum (F) visible light (G) gamma rays | C | The only light that people can see is called visible light. It refers to a very narrow range of wavelengths in the electromagnetic spectrum that falls between infrared light and ultraviolet light. Within the visible range, we see light of different wavelengths as different colors of light, from red light, which has the... |
electromagnetic waves with the longest wavelengths | (A) radio waves (B) infrared light (C) ultraviolet light (D) microwaves (E) electromagnetic spectrum (F) visible light (G) gamma rays | A | Electromagnetic waves on the left side of the Figure 1.1 are called radio waves. Radio waves are electromagnetic waves with the longest wavelengths. They may have wavelengths longer than a soccer field. They are also the electromagnetic waves with the lowest frequencies. With their low frequencies, they have the least ... |
light with the longest wavelengths | (A) radio waves (B) infrared light (C) ultraviolet light (D) microwaves (E) electromagnetic spectrum (F) visible light (G) gamma rays | B | Light with the longest wavelengths is called infrared light. The term infrared means below red. Infrared light is the range of light waves that have longer wavelengths and lower frequencies than red light in the visible range of light waves. The sun gives off infrared light as do flames and living things. You cant see ... |
radio waves with the highest frequencies | (A) radio waves (B) infrared light (C) ultraviolet light (D) microwaves (E) electromagnetic spectrum (F) visible light (G) gamma rays | D | The shortest wavelength, highest frequency radio waves are called microwaves (see Figure 21.7). Microwaves have more energy than other radio waves. Thats why they are useful for heating food in microwave ovens. Microwaves have other important uses as well, including cell phone transmissions and radar, which is a device... |
referring to matter that allows all visible light to pass through | (A) incandescence (B) translucent (C) pigment (D) luminescence (E) transmission (F) transparent (G) opaque | F | Matter can be classified on the basis of how light interacts with it. Matter may be transparent, translucent, or opaque. Each type of matter is illustrated in Figure 22.3. Transparent matter is matter that transmits light without scattering it. Examples of transparent matter include air, pure water, and clear glass. Yo... |
Light bulbs that produce light by electroluminescence include | (A) neon light bulbs (B) vapor light bulbs (C) LED light bulbs (D) all of the above | D | The classroom in Figure 22.1 has artificial light sources in addition to natural sunlight. There are fluorescent lights on the ceiling of the room. There are also projectors on the ceiling that are shining light on screens. In these and most other artificial light sources, electricity provides the energy and some type ... |
production of visible light in a way that does not require high temperatures | (A) incandescence (B) translucent (C) pigment (D) luminescence (E) transmission (F) transparent (G) opaque | D | Some objects produce light without becoming very hot. They generate light through chemical reactions or other processes. Producing light without heat is called luminescence. Luminescence, in turn, can occur in several different ways: One type of luminescence is called fluorescence. In this process, a substance absorbs ... |
You can see clearly through an object that is transparent because all of the light that strikes the object is | (A) transmitted (B) reflected (C) refracted (D) absorbed | A | An opaque object is one that doesnt let light pass through it. Instead, it reflects or absorbs the light that strikes it. Many objects, such as the leaves pictured in the Figure 1.3, reflect just one or a few wavelengths of visible light and absorb the rest. The wavelengths that are reflected determine the color that a... |
referring to matter that does not allow visible light to pass through it | (A) incandescence (B) translucent (C) pigment (D) luminescence (E) transmission (F) transparent (G) opaque | G | Matter can be classified on the basis of how light interacts with it. Matter may be transparent, translucent, or opaque. Each type of matter is illustrated in Figure 22.3. Transparent matter is matter that transmits light without scattering it. Examples of transparent matter include air, pure water, and clear glass. Yo... |
The shortest wavelength of visible light appears to the human eye as the color | (A) red (B) violet (C) yellow (D) magenta | B | Visible light is light that has wavelengths that can be detected by the human eye. The wavelength of visible light determines the color that the light appears. As you can see in the Figure 1.1, light with the longest wavelength appears red, and light with the shortest wavelength appears violet. In between are all the o... |
Why does a blackboard appear black? | (A) It reflects all wavelengths of visible light (B) It absorbs all wavelengths of visible light (C) It reflects only black wavelengths of visible light (D) It absorbs only black wavelengths of visible light | B | We see an opaque object, such as the apple in Figure 22.6, because it reflects some wavelengths of visible light. The wavelengths that are reflected determine the color that the object appears. For example, the apple in the figure appears red because it reflects red light and absorbs light of other wavelengths. We see ... |
production of visible light by an object that is so hot it glows | (A) incandescence (B) translucent (C) pigment (D) luminescence (E) transmission (F) transparent (G) opaque | A | The sun and other stars produce light because they are so hot. They glow with light due to their extremely high temperatures. This way of producing light is called incandescence. Some objects produce light without becoming very hot. They generate light through chemical reactions or other processes. Producing light with... |
passage of light through matter | (A) incandescence (B) translucent (C) pigment (D) luminescence (E) transmission (F) transparent (G) opaque | E | Transmission of light occurs when light passes through matter. As light is transmitted, it may pass straight through matter or it may be refracted or scattered as it passes through. When light is refracted, it changes direction as it passes into a new medium and changes speed. The straw in the Figure 1.2 looks bent whe... |
Which of the following colors is a primary pigment color? | (A) red (B) blue (C) cyan (D) green | C | Many objects have color because they contain pigments. A pigment is a substance that colors materials by reflecting light of certain wavelengths and absorbing light of other wavelengths. A very common pigment is the dark green pigment called chlorophyll, which is found in plants. Chlorophyll absorbs all but green wavel... |
referring to matter that transmits but scatters visible light | (A) incandescence (B) translucent (C) pigment (D) luminescence (E) transmission (F) transparent (G) opaque | B | Matter can be classified on the basis of how light interacts with it. Matter may be transparent, translucent, or opaque. Each type of matter is illustrated in Figure 22.3. Transparent matter is matter that transmits light without scattering it. Examples of transparent matter include air, pure water, and clear glass. Yo... |
substance that colors materials by reflecting light of certain wavelengths and absorbing light of other | (A) incandescence (B) translucent (C) pigment (D) luminescence (E) transmission (F) transparent (G) opaque | C | Many objects have color because they contain pigments. A pigment is a substance that colors materials by reflecting light of certain wavelengths and absorbing light of other wavelengths. A very common pigment is chlorophyll, which is found in plants. This dark green pigment absorbs all but green wavelengths of visible ... |
A luminous object is an object that appears to glow because it is reflecting light from another source. | (A) true (B) false | B | Many other objects appear to produce their own light, but they actually just reflect light from another source. Being lit by another source is called illumination. The moon in the Figure 1.4 is glowing so brightly that you can see shadows under the trees. It appears to glow from its own light, but its really just illum... |
Some minerals produce visible light when they absorb ultraviolet light. | (A) true (B) false | A | Some objects produce light without becoming very hot. They generate light through chemical reactions or other processes. Producing light without heat is called luminescence. Luminescence, in turn, can occur in several different ways: One type of luminescence is called fluorescence. In this process, a substance absorbs ... |
A neon light produces violet or blue light. | (A) true (B) false | B | A neon light produces visible light by electroluminescence. In this process, neon or some other gas gives off light when an electric current passes through it. Other halogen gases besides neonincluding krypton and argonalso produce light in this way. The word OPEN in the sign 1.3 is a neon light. It is a long glass tub... |
An object that reflects all the light that strikes it is opaque. | (A) true (B) false | A | An opaque object is one that doesnt let light pass through it. Instead, it reflects or absorbs the light that strikes it. Many objects, such as the leaves pictured in the Figure 1.3, reflect just one or a few wavelengths of visible light and absorb the rest. The wavelengths that are reflected determine the color that a... |
Fireflies glow with visible light because of chemical reactions. | (A) true (B) false | A | Some objects produce light without becoming very hot. They generate light through chemical reactions or other processes. Producing light without heat is called luminescence. Luminescence, in turn, can occur in several different ways: One type of luminescence is called fluorescence. In this process, a substance absorbs ... |
The sun and other stars produce visible light by | (A) fluorescence (B) luminescence (C) incandescence (D) electroluminescence | C | Most of the visible light on Earth comes from the sun. The sun and other stars produce light because they are so hot. They glow with light due to their extremely high temperatures. This way of producing light is called incandescence. Incandescent light bulbs also produce light in this way. When electric current passes ... |
Jellyfish and fireflies produce light as a result of | (A) high temperatures (B) chemical reactions (C) absorption of ultraviolet light (D) reflection of light from other sources | B | Some objects produce light without becoming very hot. They generate light through chemical reactions or other processes. Producing light without heat is called luminescence. Luminescence, in turn, can occur in several different ways: One type of luminescence is called fluorescence. In this process, a substance absorbs ... |
Which type of light bulb produces visible light by electroluminescence? | (A) incandescent light bulb (B) vapor light bulb (C) neon light bulb (D) two of the above | D | The classroom in Figure 22.1 has artificial light sources in addition to natural sunlight. There are fluorescent lights on the ceiling of the room. There are also projectors on the ceiling that are shining light on screens. In these and most other artificial light sources, electricity provides the energy and some type ... |
An example of opaque matter is a | (A) clear glass window (B) wooden door (C) mirror (D) two of the above | D | Matter can be classified on the basis of its interactions with light. Matter may be transparent, translucent, or opaque. An example of each type of matter is pictured in the Figure 1.4. Transparent matter is matter that transmits light without scattering it. Examples of transparent matter include air, pure water, and c... |
Light with the longest wavelength appears | (A) red (B) blue (C) green (D) violet | A | Visible light is light that has wavelengths that can be detected by the human eye. The wavelength of visible light determines the color that the light appears. As you can see in the Figure 1.1, light with the longest wavelength appears red, and light with the shortest wavelength appears violet. In between are all the o... |
A prism separates light into different colors by | (A) reflection (B) refraction (C) scattering (D) transmission | B | A prism, like the one in Figure 22.5, can be used to separate visible light into its different colors. A prism is a pyramid-shaped object made of transparent matter, usually clear glass. It transmits light but slows it down. When light passes from the air to the glass of the prism, the change in speed causes the light ... |
If only green light strikes a blue object, the object appears | (A) green (B) blue (C) black (D) white | C | We see an opaque object, such as the apple in Figure 22.6, because it reflects some wavelengths of visible light. The wavelengths that are reflected determine the color that the object appears. For example, the apple in the figure appears red because it reflects red light and absorbs light of other wavelengths. We see ... |
All plants use visible light to make food by photosynthesis. | (A) true (B) false | A | The organisms pictured in the Figures 1.1, 1.2, and 1.3 all use sunlight to make glucose in the process of photo- synthesis. In addition to plants, they include bacteria and algae. All of these organisms contain the green pigment chlorophyll, which is needed to capture light energy. A tremendous amount of photosynthesi... |
The moon is an example of a luminescent object. | (A) true (B) false | B | Many other objects appear to produce their own light, but they actually just reflect light from another source. Being lit by another source is called illumination. The moon in the Figure 1.4 is glowing so brightly that you can see shadows under the trees. It appears to glow from its own light, but its really just illum... |
The filament of an incandescent light bulb glows because it gets extremely hot. | (A) true (B) false | A | An incandescent light bulb like the one pictured in the Figure 1.1 produces visible light by incandescence. Incan- descence occurs when something gets so hot that it glows. An incandescent light bulb contains a thin wire filament made of tungsten. When electric current passes through the filament, it gets extremely hot... |
An LED light produces visible light by fluorescence. | (A) true (B) false | B | A fluorescent light bulb produces visible light by fluorescence. Fluorescence occurs when a substance absorbs shorter-wavelength ultraviolet light and then gives off the energy as visible light. The compact fluorescent light bulb (CFL) in the Figure 1.2 contains mercury gas that gives off ultraviolet light when electri... |
You can see clearly through an object that is translucent. | (A) true (B) false | B | Matter can be classified on the basis of how light interacts with it. Matter may be transparent, translucent, or opaque. Each type of matter is illustrated in Figure 22.3. Transparent matter is matter that transmits light without scattering it. Examples of transparent matter include air, pure water, and clear glass. Yo... |
A rainbow occurs because raindrops separate light into its different wavelengths. | (A) true (B) false | A | A prism, like the one in Figure 22.5, can be used to separate visible light into its different colors. A prism is a pyramid-shaped object made of transparent matter, usually clear glass. It transmits light but slows it down. When light passes from the air to the glass of the prism, the change in speed causes the light ... |
An apple appears red because it absorbs only red light. | (A) true (B) false | B | We see an opaque object, such as the apple in Figure 22.6, because it reflects some wavelengths of visible light. The wavelengths that are reflected determine the color that the object appears. For example, the apple in the figure appears red because it reflects red light and absorbs light of other wavelengths. We see ... |
The bluish green color called cyan is a secondary color of light. | (A) true (B) false | A | The human eye can distinguish only red, green, and blue light. These three colors are called the primary colors of light. All other colors of light can be created by combining the primary colors. Look at the Venn diagram 1.5. Red and green light combine to form yellow light. Red and blue light combine to form magenta l... |
Combining red, green, and blue light produces light that appears to be black. | (A) true (B) false | B | The human eye can distinguish only red, green, and blue light. These three colors are called the primary colors of light. All other colors of light can be created by combining the primary colors. Look at the Venn diagram 1.5. Red and green light combine to form yellow light. Red and blue light combine to form magenta l... |
The primary colors of pigments are the same as the primary colors of light. | (A) true (B) false | B | Many objects have color because they contain pigments. A pigment is a substance that colors materials by reflecting light of certain wavelengths and absorbing light of other wavelengths. A very common pigment is the dark green pigment called chlorophyll, which is found in plants. Chlorophyll absorbs all but green wavel... |
formation of a clear image by light reflected from a very smooth surface | (A) convex (B) laser (C) concave (D) regular reflection (E) optics (F) image (G) diffuse reflection | D | Reflection of light occurs when light bounces back from a surface that it cannot pass through. Reflection may be regular or diffuse. If the surface is very smooth, like a mirror, the reflected light forms a very clear image. This is called regular, or specular, reflection. In the Figure 1.1, the smooth surface of the s... |
A convex lens | (A) is thicker at the edges than in the middle (B) forms only real upside-down images (C) may form enlarged or reduced images (D) causes rays of light to diverge | C | A convex lens is thicker in the middle than at the edges. You can see the shape of a convex lens in the Figure 1.2. A convex lens causes rays of light to converge, or meet, at a point called the focus (F). A convex lens forms either a real or virtual image. It depends on how close the object is to the lens relative to ... |
device that produces a very focused beam of light of just one wavelength | (A) convex (B) laser (C) concave (D) regular reflection (E) optics (F) image (G) diffuse reflection | B | Did you ever see a cat chase after a laser light, like the one in Figure 1.4? A laser is a device that produces a very focused beam of visible light of just one wavelength and color. Waves of laser light are synchronized so the crests and troughs of the waves line up. The diagram in Figure 1.4 shows why a beam of laser... |
Concave mirrors are used | (A) as side mirrors on cars (B) behind car headlights (C) in compound microscopes (D) in cameras | B | Some mirrors have a curved rather than flat surface. Curved mirrors can be concave or convex. A concave mirror is shaped like the inside of a bowl. This type of mirror forms either real or virtual images, depending on where the object is placed relative to the focal point. The focal point is the point in front of the m... |
curving outward like the outside of a bowl | (A) convex (B) laser (C) concave (D) regular reflection (E) optics (F) image (G) diffuse reflection | A | The other type of curved mirror, a convex mirror, is shaped like the outside of a bowl. This type of mirror forms only virtual images. The image is always right-side up and smaller than the actual object, which makes the object appear farther away than it really is. You can see how a convex mirror forms an image in Fig... |
The optical instrument that produces a beam of very focused light is a | (A) laser (B) microscope (C) telescope (D) none of the above | A | Mirrors and lenses are used in optical instruments to reflect and refract light. Optical instruments include micro- scopes, telescopes, cameras, and lasers. |
Which surface is most likely to result in diffuse reflection? | (A) completely still water in a puddle (B) choppy water in a lake (C) a plane glass mirror (D) a convex mirror | B | Reflection of light occurs when light bounces back from a surface that it cannot pass through. Reflection may be regular or diffuse. If the surface is very smooth, like a mirror, the reflected light forms a very clear image. This is called regular, or specular, reflection. In the Figure 1.1, the smooth surface of the s... |
copy of an object that is formed by reflected or refracted light | (A) convex (B) laser (C) concave (D) regular reflection (E) optics (F) image (G) diffuse reflection | F | Reflection is one of several ways that light can interact with matter. Light reflects off surfaces such as mirrors that do not transmit or absorb light. When light is reflected from a smooth surface, it may form an image. An image is a copy of an object that is formed by reflected (or refracted) light. Q: Is an image a... |
formation of a blurry image by light reflected from a rough surface | (A) convex (B) laser (C) concave (D) regular reflection (E) optics (F) image (G) diffuse reflection | G | Reflection of light occurs when light bounces back from a surface that it cannot pass through. Reflection may be regular or diffuse. If the surface is very smooth, like a mirror, the reflected light forms a very clear image. This is called regular, or specular, reflection. In the Figure 1.1, the smooth surface of the s... |
A compound microscope contains | (A) convex lenses (B) plane mirror (C) convex mirror (D) two of the above | D | A light microscope is an instrument that uses lenses to make enlarged images of objects that are too small for the unaided eye to see. A common type of light microscope is a compound microscope, like the one in Figure 22.18. A compound microscope has at least two convex lenses: one or more objective lenses and one or m... |
curving inward like the inside of a bowl | (A) convex (B) laser (C) concave (D) regular reflection (E) optics (F) image (G) diffuse reflection | C | The other type of curved mirror, a convex mirror, is shaped like the outside of a bowl. This type of mirror forms only virtual images. The image is always right-side up and smaller than the actual object, which makes the object appear farther away than it really is. You can see how a convex mirror forms an image in Fig... |
study of visible light and the ways it can be used | (A) convex (B) laser (C) concave (D) regular reflection (E) optics (F) image (G) diffuse reflection | E | Optics is the study of visible light and the ways it can be used to extend human vision and do other tasks. Knowledge of light was needed for the invention of optical instruments such as microscopes, telescopes, and cameras, in addition to optical fibers. These instruments use mirrors and lenses to reflect and refract ... |
Moving the lens of a camera controls the amount of light that enters the camera. | (A) true (B) false | B | A camera is an optical instrument that forms and records an image of an object. The image may be recorded on film or it may be detected by an electronic sensor that stores the image digitally. Regardless of how the image is recorded, all cameras form images in the same basic way, as shown in the Figure 1.3. Light passe... |
A laser beam consists of photons of light of a single wavelength. | (A) true (B) false | A | Did you ever see a cat chase after a laser light, like the one in Figure 1.4? A laser is a device that produces a very focused beam of visible light of just one wavelength and color. Waves of laser light are synchronized so the crests and troughs of the waves line up. The diagram in Figure 1.4 shows why a beam of laser... |
A reflecting telescope does not refract light. | (A) true (B) false | B | Humans have been making and using magnifying lenses for thousands of years. The first telescope was built by Galileo in 1608. His telescope used two lenses to make distant objects appear both nearer and larger. Telescopes that use lenses to bend light are called refracting telescopes, or refractors (Figure 23.4). The e... |
Magnifications of all the lenses of a microscope are added to yield the overall magnification of the | (A) true (B) false | B | A light microscope is an instrument that uses lenses to make enlarged images of objects that are too small for the unaided eye to see. A common type of light microscope is a compound microscope, like the one in Figure 22.18. A compound microscope has at least two convex lenses: one or more objective lenses and one or m... |
Light refracts when it enters a new medium at an angle other than 90 . | (A) true (B) false | A | When light passes from one medium (or type of matter) to another, it changes speed. You can actually see this happen. If light strikes a new substance at an angle, the light appears to bend. This is what explains the straw looking broken in the picture above. So, does light always bend as it travels into a new medium? ... |
Only mirrors reflect light and form images. | (A) true (B) false | B | Mirrors are usually made of glass with a shiny metal backing that reflects all the light that strikes it. Mirrors may have flat or curved surfaces. The shape of a mirrors surface determines the type of image the mirror forms. For example, the image may be real or virtual. A real image forms in front of a mirror where r... |
All mirrors can form virtual images. | (A) true (B) false | A | Mirrors are usually made of glass with a shiny metal backing that reflects all the light that strikes it. Mirrors may have flat or curved surfaces. The shape of a mirrors surface determines the type of image the mirror forms. For example, the image may be real or virtual. A real image forms in front of a mirror where r... |
The image formed by a plane mirror looks exactly like the object in every way. | (A) true (B) false | B | Most mirrors are plane mirrors. A plane mirror has a flat reflective surface and forms only virtual images. The image formed by a plane mirror is also life sized. But something is different about the image compared with the real object in front of the mirror. Left and right are reversed. Look at the man shaving in Figu... |
The focal point of a concave mirror is the point in front of the mirror where reflected rays intersect. | (A) true (B) false | A | Some mirrors have a curved rather than flat surface. Curved mirrors can be concave or convex. A concave mirror is shaped like the inside of a bowl. This type of mirror forms either real or virtual images, depending on where the object is placed relative to the focal point. The focal point is the point in front of the m... |
A concave mirror can form only virtual images. | (A) true (B) false | B | Some mirrors have a curved rather than flat surface. Curved mirrors can be concave or convex. A concave mirror is shaped like the inside of a bowl. This type of mirror forms either real or virtual images, depending on where the object is placed relative to the focal point. The focal point is the point in front of the m... |
The image formed by a convex mirror is always upright and reduced in size. | (A) true (B) false | A | The other type of curved mirror, a convex mirror, is shaped like the outside of a bowl. This type of mirror forms only virtual images. The image is always right-side up and smaller than the actual object, which makes the object appear farther away than it really is. You can see how a convex mirror forms an image in Fig... |
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