Which technology uses low frequency (LF) radio waves?
O
O
space communication
FM radio broadcasting
TV program broadcasting
submarine communication

Submarine communication uses low frequency radio waves.

Explanation:

Submarine communications of submerged submarines to the outside are mostly restricted or limited by the depth at which the submarine vessels are submerged deep in the ocean (below the level where sonar cannot identify) and the speed at which the communication can travel through the water medium. Further, Seawater’s electrical conductivity prevents high-frequency waves.  

In order to cope up with this problem, extremely low frequency and very low-frequency radio waves are used for submarine communication since LF radio waves can penetrate deep into the ocean or sea waters.

force required to detach it is given by

charges are taken to be fundamental charge

now we have

so above is the minimum distance at which it will detach