NEET · Physics · STD 12 - 9. Ray optics and optical instruments
Two thin lenses are of same focal lengths \((f)\), but one is convex and the other one is concave. When they are placed in contact with each other, the equivalent focal length of the combination will be:
- A Infinite
- B Zero
- C \(f / 4\)
- D \(f / 2\)
Answer & Solution
Correct Answer
(A) Infinite
Step-by-step Solution
Detailed explanation
\(\frac{1}{f_{e q}}=\frac{1}{f_1}+\frac{1}{f_2}\) \(\frac{1}{f_{e q}}=\frac{1}{f}-\frac{1}{f}\)
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