Question

Single
Two parallel rays incident on the
combination of two lenses A and B
placed in close contact as shown below.
Then choose the correct option among
the following
AB
a. Both A and B can be concave lens
b. Both A and B can be convex lens
c. A can be convex and B can be
concave but power of B must be greater
than power of A
d. A can be concave and B can be​​

Answer 1

Answer:

it's C. The most appropriate answer to this Qs is C.

Answer 2

(c) A can be convex and B can beconcave but power of B must be greater than the power of A.

To do such qualitative questions see the initial and final conditions of rays. initially, rays are parallel and finally, they become diverging rays.

⇒ the net nature of the system is diverging.

option c suggests that lens A is convex which means it will converge the rays. Now, for the final rays to be diverging B must be concave and should also be of higher power to overshadow the effect of lens A(converging). Hence, c is the correct option.