ACT Waves by Y51jP30

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ACT Prep: Waves

           USING SCIENCE SKILLS
                                                                                                                  Figure 17-2

        1. Interpreting Illustrations What kind of wave                                                                  does
           A in Figure 17-2 represent? What kind of wave                                                                 does
           B represent?
        2. Comparing and Contrasting Figure 17-2 shows                                                                   how
           someone starts the waves. How are these ways of
           starting waves alike? How are they different?
        3. Inferring Compare the two waves in Figure 17-                                                                 2.
           To what in wave B do the compressions of wave                                                                 A
           correspond? To what in wave B do the
           rarefactions correspond?


        4. Inferring What represents one wavelength in wave A of Figure 17-2? Define and describe the portion of the
           wave.
        5. Using Analogies In Figure 17-2, wave A is produced by a spring toy, representing the concept of a sound wave in
           air. In sound, what is being squeezed together in the compressions, and what is being released in the rarefactions?

                                                                                                                  Figure 17-3

        6. Analyzing Data What is the difference between wave                                                             A
           and wave B in Figure 17-3?
        7. Inferring In Figure 17-3, both wave A and wave B
           were started by the same type of force—an up-and-
           down motion. What conclusion can you make about                                                                the
           energy of these two wave-starting forces?
        8. Predicting Suppose you add the following panel E to                                                            the
           diagram: a wave pattern with a frequency of four
           waves per second. How will wavelength in this panel
           compare with the wavelength in panel D? How will it
           compare with the wavelength in panel C? Assume all                                                             the
           waves travel at the same speed.
        9. Analyzing Data What is the difference between wave                                                             C
           and wave D in Figure 17-3?
    10. Drawing Conclusions Consider both frequency and wavelength in Figure 17-3. How does each variable change
        between wave C and wave D? What is the relationship that explains the change? Assume the waves travel at the
        same speed.


           USING SCIENCE SKILLS
                                       Figure 18-2

11. Comparing and Contrasting Which waves in Figure 18-2 carry AM and FM signals? How do the frequencies of
    AM and FM signals compare?
12. Analyzing Data How does photon energy change with increasing frequency? Use Figure 18-2 to answer this
    question.
13. Interpreting Graphics Which waves in Figure 18-2 are used to expose heat-sensitive film? Where are these
    waves located in the electromagnetic spectrum?
14. Classifying In Figure 18-2, which waves can be separated into different wavelengths of colored light?
15. Inferring Look at Figure 18-2. Without referring to the specific frequencies and wavelengths of the colors of the
    visible spectrum, at which end of the visible spectrum would you place red? At which end would you place
    violet? Hint: Use the names of the waves outside the visible spectrum to help you.
ACT Prep
Answer Section: Waves

     1. ANS:
        a longitudinal wave; a transverse wave

        DIF: L1
     2. ANS:
        Both waves are started by application of a force. However, wave A, the longitudinal wave, is started by a back-
        and-forth, or push-and-pull, movement in the same direction as the resulting wave movement, while wave B, the
        transverse wave, is started by an up-and down movement that is at right angles to the resulting direction in which
        the wave travels.

        DIF: L1
     3. ANS:
        Compressions in wave A correspond to crests in wave B. Rarefactions in wave A correspond to troughs in wave
        B. Each of these conditions represents an extreme in which the coil is being displaced from its rest position.

        DIF: L1
     4. ANS:
        In wave A, one wavelength equals the distance between center of a compression in the spring toy and the
        corresponding location in the next compression. Wavelength is the distance between a point on one wave and the
        same point on the next cycle of waves.

        DIF: L1
     5. ANS:
        In a sound wave in air, the compressions consist of regions of bunched-up air, while the rarefactions consist of
        regions in which the molecules are more spread out.

        DIF: L1
     6. ANS:
        Wave B has an amplitude that is one half the amplitude of wave A.

        DIF: L2
     7. ANS:
        The force that caused wave A added more energy to the wave than the force that caused wave B.

        DIF: L2
     8. ANS:
        The wavelength in E will be one half that of the wavelength in D; it will be one fourth that of the wavelength in C.

        DIF: L2
     9. ANS:
        Wave D has a frequency twice that of wave C; Therefore, the wavelength in wave D is one half that of wave C.

        DIF: L2
    10. ANS:
        Between wave C and wave D, frequency doubles, but wavelength is halved. Wavelength is inversely proportional
        to frequency.
    DIF: L2
11. ANS:
    Radio waves; FM signals usually have higher frequencies than AM signals have.

    DIF: L1
12. ANS:
    High-frequency waves such as X-rays and gamma rays have higher energy photons than lower-frequency waves
    such as radio waves and infrared rays.

    DIF: L1
13. ANS:
    infrared rays; between visible light and microwaves

    DIF: L1
14. ANS:
    visible light

    DIF: L1
15. ANS:
    Red would be at the end of the visible spectrum with the lowest frequency and longest wavelength of all the
    colors, just above the infrared range. Infra- means “under,” so infrared- means “under red.” In the same way,
    ultra- means “beyond,” so ultraviolet means “beyond violet.” Violet would be at the end of the visible spectrum
    with the shortest wavelength and the highest frequency.

     DIF: L1

								
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