Calculate the wavelength of each of the following frequencies of electromagnetic radiation.

Question

Calculate the wavelength of each of the following frequencies of electromagnetic radiation.

1. 104.7 MHz (typical frequency for FM radio broadcasting)
2. 1370 kHz (typical frequency for AM radio broadcasting) (assume four significant figures)
3. 894.5 MHz  (common frequency used for cell phone communication)

Answer 1

Electromagnetic radiation travels at the speed of light which is 2.998 x 10⁸ m/s so we can use the equation:

(wavelength)(frequency) = (speed of light)

λ•f = c

λ = c/f

So for problem 1, λ = (2.998 x 10⁸)/(104.7 x 10⁶) = 2.863 m

For problem 2, λ = (2.998 x 10⁸)/(1370 x 10³) = 219 m

For problem 3, λ = (2.998 x 10⁸)/(894.5 x 10⁶) = 0.3352 m = 33.52 cm