How is the electromagnetic force different than both the gravitational force and the strong nuclear force? it has an infinite range. it acts at the subatomic level. it is repulsive. it holds protons together.

It is repulsive.

Explanation:

Electromagnetic force is attractive in nature when acts between two unlike charges and repulsive in nature when acts between like charges. It has infinite range. It does not hold protons together because it is repulsive in nature between two protons.

Gravitational force is always attractive in nature. It acts between any two  bodies having mass. It has infinite range.

Strong nuclear force acts at subatomic level ( nucleus of an atom ). It is attractive in nature. It holds protons together inside the nucleus. It does not have infinite range.

Hence, electromagnetic force is different from both the gravitational force and the strong nuclear force as the later two are attractive but electromagnetic force is repulsive as well.

convex lenses are thicker at the middle. rays of light that pass through the lens are brought closer together (they converge). a convex lens is a converging lens. when parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.