Question

The radio waves that travel through the air to our car/truck/home radios are just another type of light. Let's say that your favorite radio station is 87.9 on the FM dial. That means that those radio waves have a frequency of 87.9 MHz. (a) What are the wavelength and energy of those radio waves? (b) How fast would these radio waves travel through water?

Answer 1

Answer:

Explanation:

(a) Electromagnetic waves travels at the speed of light = 3.0 x $10^{8}$ m/s.

v = fλ

where v is the velocity of the wave, f is the frequency, and λ wavelength.

So that;

λ = $\frac{v}{f}$

  = $\frac{3.0*10^{8} }{87.9*10^{6} }$

  = 3.413 m

ii. Enegy of the wave can be determined by;

E = hf

where h is the Planck's constant and f the frequency of the wave.

E = 6.626 x $10^{-34}$ x 87.9 x $10^{6}$

  = 5.82 x $10^{-26}$ J

(b) Refractive index of water = $\frac{velocity of light in air}{velocity of light in water}$

velocity of light in water = 1.33 x 3.0 x $10^{8}$

       = 3.99 x $10^{8}$ m/s