Homework Helpers: Physics

8 Waves and Light

Chapter 8 Examination

Part I—Matching

Match the following terms to the definitions that follow.

a. crest

b. trough

c. wavelength

d. amplitude

e. mechanical wave

f. electromagnetic wave

g. transverse wave

h. longitudinal wave

i. frequency

j. compression

k. convex

l. concave

_____1. A transverse wave that is capable of traveling through a vacuum.

_____2. An area in a material medium where the particles are more densely packed.

_____3. The distance measured from a point on one cycle to the same point on the next cycle.

_____4. The number of vibrations or cycles of motion in a second, usually measured in hertz.

_____5. The maximum displacement of the particles of a medium from their rest position.

_____6. A wave in which the particles of the medium vibrate back and forth along the same axis in which the wave travels.

_____7. The type of curved mirror with the shiny surface on the outside of the curve.

_____8. A wave that requires a medium through which to travel.

_____9. This type of lens is also called a “diverging” lens.

_____10. The lowest point of a wave.

Part II—Multiple Choice

For each of the following questions, choose the best answer.

11. Which of the following is not an example of a transverse wave?

a) visible light

b) gamma waves

c) x-rays

d) sound waves

12. Which characteristic of sound waves is associated with what we call “loudness”?

a) amplitude

b) frequency

c) period

d) wavelength

13. An incident ray of light with an angle of 35.0° from the normal strikes a plane (flat) mirror. What will be the angle of reflection, measured to the normal of the medium?

a) 180.0°

b) 90.0°

c) 550.0°

d) 35.0°

14. Which of the following could not be explained with the particle-theory of light?

a) reflection

b) refraction

c) interference

d) color

Part III—Calculations

Perform each of the following calculations.

15. The index of refraction for a particular piece of glass is 1.60. Assuming the glass is surrounded by air (n = 1.00), what is the critical angle of incidence for light starting inside the glass?

16. A light bulb with a height of 10.0 cm is placed at a distance of 34.0 cm in front of a convex mirror that has a focal length of 16.0 cm. Find the distance that the image is formed from the mirror, and the height of the image.

17. A 6.50 cm tall candle is placed 14.0 cm from a concave mirror with a focal length of 6.00 cm. Find the distance that the image is formed from the mirror and the height of the image.

18. Calculate the speed of a wave with a frequency of 15,000 Hz and a wavelength of 0.022 m.

19. Calculate the wavelength of a wave with a speed of 380 m/s and a period of 0.65 s.

20. How fast would light travel in a medium with an index of refraction of 1.2?