Echolocation is the process of finding objects by emitting sounds and interpreting their reflections. This process uses echo. When sound is produced, it travels and hits an object. Sound bounces off the object and is reflected back. The echo produced helps to identify the location of the object and even size of the object. Echolocation is used by animals such as bats and dolphins to navigate and also hunt.
It takes work to push charge through a change of potential.
There's no change of potential along an equipotential path,
so that path doesn't require any work.
The answer for this question would be choice "<span>B. The average annual dose of background radiation is 250 times smaller than the dose linked to increased cancer risk."
You only have to compare 4.0 x 10^-4 and 1.0 x 10^-1. And if you can observe carefully, when you try to multiply the average annual dose of background radiation by 250, you would get 0.1 which is equivalent to the amount of annual dose linked to increased cancer risk. Therefore, the answer is B.</span>
