Communication with submerged submarines via radio waves is difficult because seawater is conductive and absorbs electromagnetic waves. penetration into the ocean is greater at longer wavelengths, so the united states has radio installations that transmit at 76 hz for submarine communications. what is the approximate wavelength of those extremely low-frequency waves?

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.