Question

e AM and FM radio waves are transverse waves consisting of
electric and magnetic disturbances traveling at a speed of 3.00 x 10
8
m/s. A
station broadcasts an AM radio wave whose frequency is 1230 x 10
3
Hz.
(1230 kHz on the dial) and an FM radio wave whose frequency is 99.1 x 10
6
Hz (99.1 MHz on the dial). Find the distance between adjacent crests in
each wave.

Answer 1

the distance between adjacent crests is the wavelangth λ.

λ1 =ñ/f1= 3•10^8/1230•10^3 = 243.9 m

λ2 =ñ/f2= 3•10^8/99.1•10^6 = 3.027 m

Answer 2

Waves moving on a lake have a speed of 2.0 m/s and a distance of 1.5 m between adjacent crests. (a) What is the frequency of the waves? (b) Find the period of the wave motion.