Question

A symmetric concave lens of focal length 24 cm is now placed in contact with the convex lens and the object is brought back to its original position. The image formed will be 

(a)  a real one with a magnification 4 

(b)  a real one at a distance of 40 cm 

(c)  a virtual one at a distance of 120 cm 

(d)  a virtual one with a magnification 2.5

Answer 1

Correct option  (a) a real one with a magnification 4

Explanation:

Focal length of the convex lens : f₁ = 12 cm

Focal length of the concave lens : f₂ = 24 cm

Effective focal length of the combination : 

So the image formed is real with a magnification of 4.