Question

The device used for making peepholes in the door of houses is a

Answer 1

Answer:

Conceptually, a peephole is made up of specially arranged convex lenses. It allows the user to see who is on the other side of the door for security reasons. A peephole is fitted with a telescopic fish-eye lens on the broad-end .

Answer 2

Explanation:

Concave lens curve inwards so when the light rays pass through them, light rays come together making the objects appear smaller than they really are. When you look through the spy-hole, it shows the whole area and the person knocking. Concave lens also known as Diverging lens is used in wide angle spyhole in doors.