Here's why:

* Electromagnetic force is mediated by photons, which are massless particles.

* Massless particles travel at the speed of light, and their influence extends infinitely far.

* The strength of the electromagnetic force decreases with distance, but it never truly reaches zero.

However, in practical terms, the electromagnetic force becomes very weak over long distances. This is because the force is inversely proportional to the square of the distance between the interacting charges. So, while the range is technically infinite, the force is negligible beyond a certain distance.

Examples:

* Gravity: Like the electromagnetic force, gravity also has an infinite range. However, gravity is much weaker than the electromagnetic force, making its effects less noticeable at shorter distances.

* Strong nuclear force: This force binds quarks together to form protons and neutrons. It has a very short range, only acting within the nucleus of an atom.

* Weak nuclear force: This force is responsible for radioactive decay. It also has a very short range.

Key takeaway: While the electromagnetic force technically has an infinite range, it weakens significantly over distance. Its practical range depends on the specific situation and the strengths of the interacting charges.