JEE Mains · Physics · STD 12 - 9. Ray optics and optical instruments
A thin lens made of glass (refractive index \(= 1.5\)) of focal length \(f=16\; \mathrm{cm}\) is immersed in a liquid of refractive index \(1.42 .\) If its focal length in liquid is \(f_{l},\) then the ratio \(f_{l} /f\) is closest to the integer
- A \(1\)
- B \(5\)
- C \(9\)
- D \(17\)
Answer & Solution
Correct Answer
(C) \(9\)
Step-by-step Solution
Detailed explanation
Using \(\frac{1}{f}=\left(\frac{\mu_{2}}{\mu_{1}}-1\right)\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right)\) \(\frac{1}{f}=\left(\frac{1.5}{1}-1\right)\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right)\dots ( 1)\) and…
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