Sound and Light Preview Understanding Concepts Reading Skills Interpreting Graphics

Understanding Concepts 1. A family notices that the garbage disposal in the sink sounds twice as loud as the vacuum cleaner does. If the sound of the garbage disposal is 80 dB, about how loud is the vacuum cleaner? A. 40 dB B. 70 dB C. 90 dB D. 160 dB

Understanding Concepts, continued 1. A family notices that the garbage disposal in the sink sounds twice as loud as the vacuum cleaner does. If the sound of the garbage disposal is 80 dB, about how loud is the vacuum cleaner? A. 40 dB B. 70 dB C. 90 dB D. 160 dB

Understanding Concepts, continued 2. A medical student is examining a model of the ear. Where should the student look to find the hammer, anvil, and stirrup? F. in the outer ear G. in the ear canal H. in the middle ear I. in the cochlea

Understanding Concepts, continued 2. A medical student is examining a model of the ear. Where should the student look to find the hammer, anvil, and stirrup? F. in the outer ear G. in the ear canal H. in the middle ear I. in the cochlea

Understanding Concepts, continued 3. What sounds can an ultrasound system, such as sonar, detect that the human ear cannot? A. sounds greater than 150 dB B. sounds greater than 20,000 Hz C. sounds traveling faster than 400 m/s D. sounds traveling through a medium that is denser than air

Understanding Concepts, continued 3. What sounds can an ultrasound system, such as sonar, detect that the human ear cannot? A. sounds greater than 150 dB B. sounds greater than 20,000 Hz C. sounds traveling faster than 400 m/s D. sounds traveling through a medium that is denser than air

Understanding Concepts, continued 4. Light striking a pane of glass passes through the glass, but the angle of the light changes while inside the pane of glass. What is this change called? F. refraction G. reflection H. incidence I. diffusion

Understanding Concepts, continued 4. Light striking a pane of glass passes through the glass, but the angle of the light changes while inside the pane of glass. What is this change called? F. refraction G. reflection H. incidence I. diffusion

Understanding Concepts, continued 5. A surface reflects all colors of light except for green. A light filter that allows only green light to pass through is placed between a light source and the surface. What color or colors will the surface appear to be under the filter?

Understanding Concepts, continued 5. A surface reflects all colors of light except for green. A light filter that allows only green light to pass through is placed between a light source and the surface. What color or colors will the surface appear to be under the filter? Answer: No colors, it will be black.

Understanding Concepts, continued 6. How are radar and sonar alike? How are they different?

Understanding Concepts, continued 6. How are radar and sonar alike? How are they different? Answer: They both send waves out and detect them after they reflect off distant objects. Sonar uses sound waves, and radar uses electromagnetic waves.

Understanding Concepts, continued 7. Is sound likely to travel faster through the air on a very cold day or on a very hot day? Why?

Understanding Concepts, continued 7. Is sound likely to travel faster through the air on a very cold day or on a very hot day? Why? Answer: It is likely to travel faster on a hot day because at higher temperatures air molecules collide more frequently and thus transfer wave energy faster.

STIMULATING EMISSIONS Reading Skills STIMULATING EMISSIONS Today, there is an astonishing variety of uses for lasers, from CD players to surgery. Lasers are beams of focused and concentrated light. The word laser began as an acronym for Light Amplification by the Stimulated Emission of Radiation. Laser light is created by first adding energy to a chamber that contains certain types of atoms. Elements in the noble gas family work well for lasers. This addition of energy is the stimulation. The energy is absorbed by electrons in the atoms, which causes the electrons to jump to a higher energy level. At this point, the atoms are in an excited state. They can return to their original energy level by losing the energy they gained. When the electrons return to their original energy level, the lost energy is emitted as photons. This energy is the radiation referred to in the acronym.

Reading Skills, continued STIMULATING EMISSIONS, continued The emitted photons can then strike other atoms that are in an excited state and cause them to emit photons in turn. The new photons are aimed in the same direction as the original photons. When mirrors are placed in certain positions within the chamber, the photons bounce back and forth many times and multiply, or amplify, the intensity of the photon emissions.

Reading Skills, continued 8. What optical effect is responsible for the amplification referred to in the acronym laser? A. refraction B. reflection C. dispersion D. diffusion

Reading Skills, continued 8. What optical effect is responsible for the amplification referred to in the acronym laser? A. refraction B. reflection C. dispersion D. diffusion

Reading Skills, continued 9. What happens when a photon strikes an atom that is in an excited state?

Reading Skills, continued 9. What happens when a photon strikes an atom that is in an excited state? Answer: The atom may emit a photon.

Interpreting Graphics The diagram below shows the electromagnetic spectrum, and various ranges of the spectrum are labeled. Use the diagram to answer questions 10–12. Insert Figure, p. 523 10. What is the wavelength of red light? F. about 7 m H. about 5 µm G. about 70 nm I. about 700 nm

Interpreting Graphics, continued Insert Figure, p. 523 10. What is the wavelength of red light? F. about 7 m H. about 5 µm G. about 70 nm I. about 700 nm

Interpreting Graphics, continued 11. Which of the following statements about gamma rays is true? A. They have a frequency of 1016 Hz. B. They have less energy than X rays have. C. They have more energy than X rays have. D. They have wavelengths that are greater than 10 nm. Insert Figure, p. 523

Interpreting Graphics, continued 11. Which of the following statements about gamma rays is true? A. They have a frequency of 1016 Hz. B. They have less energy than X rays have. C. They have more energy than X rays have. D. They have wavelengths that are greater than 10 nm. Insert Figure, p. 523

Interpreting Graphics, continued 12. As the wavelengths of electromagnetic waves increase, what happens to the frequency of the waves? Insert Figure, p. 523

Interpreting Graphics, continued 12. As the wavelengths of electromagnetic waves increase, what happens to the frequency of the waves? Answer: The frequency decreases. Insert Figure, p. 523

Interpreting Graphics, continued The diagram below shows a ray of light being reflected by two mirrors, which are aligned in parallel. Use this diagram to answer questions 13–14. 13. If angle θ is 40°, what is the angle of reflection on the second mirror? F. 40° H. 90° G. 50° I. 130° Insert Figure, p. 523

Interpreting Graphics, continued 13. If angle θ is 40°, what is the angle of reflection on the second mirror? F. 40° H. 90° G. 50° I. 130° Insert Figure, p. 523

Interpreting Graphics, continued 14. Are either the first or second reflections diffuse reflections? Explain. Insert Figure, p. 523

Interpreting Graphics, continued 14. Are either the first or second reflections diffuse reflections? Explain. Answer: Neither reflection is diffuse because the light ray is being reflected by mirrors, which are smooth. Insert Figure, p. 523