Electromagnetic waves do not require a medium to travel through. They can travel through empty space or matter.
It is very difficult for an atom to accept a proton. It can only be done under very special circumstances. So A and C are both incorrect. I don't see how D is possible. The atom does lose 1 electron, but how it gets 21 is think air.
The answer is B which is exactly what happens.
Answer:

Explanation:
<u>Dimensional Analysis</u>
It's given the relation between quantities A, B, and C as follows:

and the dimensions of each variable is:



Substituting the dimensions into the relation (the coefficient is not important in dimension analysis):

Operating:


Equating the exponents:


Adding both equations:

Solving:


Answer:

Pull the plates apart and you will knwo what it is lmaoo
Wrapping in insulated wire around a medal with ferromagnetic properties and applying an electric current