The speed of sound in steel is greater than it is in air because
steel is
a. more elastic than air
b. less elastic than air
c. more dense than air
d. less dense than air

For a wave of wavelength 4 m and frequency 8 waves/sec.,
a. amplitude = 32 m.
b. amplitude = 0.5 m.
c. speed =32 m/sec.
d. speed = 2 m/sec.