96.
(a) The frequency is
f =
c
λ
=
3.0
× 10
8
m/s
0.067
−15
m
= 4.5
24
Hz .
(b) In this case,the (very long) wavelength is
λ =
f
30 Hz
= 1.0
7
which is about 1.6 Earth radii.