Question

18. Sound waves in the Earth’s atmosphere will bend from warm air towards cold air because

a. the air density is lower.

b. the speed of sound is faster in cold air.

c. the speed of sound is slower in cold air.

d. of diffraction.

19. For any longitudinal or transverse wave, the speed is given by

a. the product of wavelength and period (v =

λT).

b. the product of period and frequency (v = Tf).

c. the product of wavelength and frequency (v =

λf).

d. the square root of the depth of the wave (v =

√D).

20. For a sound wave with constant speed, if the wavelength is doubled, the

a. period is doubled.

b. frequency is halved.

c. frequency is doubled.

d. speed is doubled.

21. We know the Earth has a solid inner core and liquid outer core because of

a. deep drilling core samples.

b. the way the Earth rotates.

c. the way seismic waves move through the interior of the Earth.

d. sonar.

22. Electromagnetic waves oscillate sideways to their direction of travel, while sound waves are

a. longitudinal compression waves. b. transverse waves. c. hybrid waves. d. plasma waves.

Answer 1