Question

converging lens is kept coaxially in contact with a diverging lens each of equal focal length what will be the focal length of combination

Answer 1

U have asked the question of mirror but in the figure u have attached thr question of electricity

Answer 2

The focal length of converging lens will be f and of diverging lens will be -f

Therefore equivalent focal length will be = 1/f-1/f
= 0

So, the focal length of combination will be infinity.

Hope this helps you...:)