Question

What is concave and convex lens defination in simple words

Answer 1

Concave and convex lens are are two transparent material
First let me explain what is lens?
lens is a transparent material bound by two surfaces; out of which at least one surface is spherical
A lens having both spherical surfaces, bulging outward, is a convex lens or double convex lens . It is thicker in the middle than at the edges. This lens can converge light rays incident on it . Hence it is also called as converging lens

A lens having both surfaces curved inwards is a convex lens or double concave lens. It is thicker at edges than at the middle. This lens can diverge light rays incident on it .Hence it is also called as diverging lens

 

Hope this helped u :-)

Answer 2

$\huge \underline \mathbb \pink{Answer~}$