Two plano convex lenses of same material and of focal lengths 20 cm & 5 cm should be arranged such that the combination is free from chromatic aberration. Then effective focal length of the combination will be:
A
20 cm
B
4 cm
C
12.5 cm
D
8 cm
Medium
Open in App
Updated on : 2022-09-05
Solution
Verified by Toppr
Correct option is C)
The effective focal length of the lens is,
f1=f11+f21−2f1f2f1+f2
Substituting the respective values, the effective focal length obtained is, f=12.5
Solve any question of Ray Optics and Optical Instrument with:-