When the sun's rays are focused through a magnifying glass, it's called a focal point.

Here's why:

* Magnifying glass: A convex lens that bends light rays inward.

* Focal point: The point where all the light rays converge after passing through the lens.

The concentrated heat at the focal point can be intense, enough to ignite paper or other flammable materials. It's important to be extremely cautious when using magnifying glasses and the sun, as it can cause serious burns.