Which of these is a concave lens?

The correct answer is Image 2.

Explanation:

Concave lens is defined as the lens which diverges the light falling on it. It is considered as a diverging lens.

Convex lens is defined as the lens which converges the light falling on it. It is considered as a converging lens.

Types of concave lens:

Types of convex lens:

So, image 1 is a double convex lens, image 2 is a plano-concave lens, image 3 is a plano-convex lens and image 4 is a concavo-convex lens.

Hence, the correct answer is Image 2.

second mirror gathers light from a faraway object and reflects it to another mirror. - a.

explanation:

v=uf/(u-f)

= 5.-10/(5+10) convex lens has negative focal length