Question

Communication with submerged submarines via radio waves is difficult because seawater is conductive and absorbselectromagnetic waves. Penetration into the ocean is greater at longer wavelengths, so the United States has radioinstallations that transmit at 76 Hz for submarine communications. What is the approximate wavelength of those extremelylow-frequency waves?A. 500 kmB. 1000 kmC. 2000 kmD. 4000 km

Answer 1

Answer:

D. 4000 km

Explanation:

f = Frequency of wave that is being transmitted = 76 Hz

$\lambda$ = Wavelength of wave that is being transmitted

v = The velocity of electromagnetic waves through air = $3\times 10^8\ m/s$

Velocity of a wave is given by

$v=f\lambda\\\Rightarrow \lambda=\frac{v}{f}\\\Rightarrow \lambda=\frac{3\times 10^8}{76}\\\Rightarrow \lambda=3947368.42105\ m=3947.36842105 km\approx 4000\ km$

Hence, the approximate wavelength of the waves is 4000 km