WBJEE · Physics · Ray Optics
Two thin lenses of focal lengths \(20 \mathrm{~cm}\) and \(25 \mathrm{~cm}\) are placed in cotact. The effective power of the combination is
- A 9D
- B \(2 \mathrm{D}\)
- C 3D
- D \(\mathrm{TD}\)
Answer & Solution
Correct Answer
(A) 9D
Step-by-step Solution
Detailed explanation
Hints: \(P=P_1+P_2\) \(=\frac{1}{f_1}+\frac{1}{f_2}=\frac{100}{20}+\frac{100}{25}=5+4=9 D\)
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