Force between two charges =
( 1/4πε₀ ) · (Charge #1) · (Charge #2) / (Distance between them)²
in the direction away from each other.
In other words, if the force is positive, the charges are repelling.
If the force is negative, the charges are attracting.
Find the intensity of the electromagnetic wave described in each case.
(a) an electromagnetic wave with a wavelength of 645 nm and a peak electric field magnitude of 8.5 V/m.
(b) an electromagnetic wave with an angular frequency of 6.3 ✕ 1018 rad/s and a peak magnetic field magnitude of 10−10 T.
Answer:
a) 1.2*10^{-3}cos(1.25t)
b) 0.49mV
Explanation:
a) The coil rotates periodically with period T. Hence, we can write the variation of the magnetic flux with a sinusoidal function, and with max flux NAB. Thus, we have that:

where we have used the values given by the information of the problem for N B and A.
b)
the emf is given by:

hope this helps!!
Electrostatic forces between charges depend on the product of
the sizes of the charges, and the distance between them.
We should also mention the item about whether the charges are
both the same sign or opposite signs. That determines whether
the forces will pull them together or push them apart, which is a
pretty significant item.