Two convex lenses with power 2 dioptre are kept in contact with each other. The focal length of the combined lens system is
0.10 m
2 m
4 m
0.25 m
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC NDA-1 – 2018
Given the power of each lens is 2 Dioptre, the total power of the combined system is $P_{total} = P_1 + P_2 = 2 \, \text{D} + 2 \, \text{D} = 4 \, \text{D}$.
The focal length of the combined lens system (F) is the reciprocal of the total power: $F = 1 / P_{total} = 1 / 4 \, \text{D} = 0.25 \, \text{meters}$.