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JEE Mains · Physics · STD 12 - 9. Ray optics and optical instruments
A compound microscope consists of an objective lens of focal length \(1 \,cm\) and an eye piece of focal length \(5 \,cm\) with a separation of \(10 \,cm\) The distance between an object and the objective lens, at which the strain on the eye is minimum is \(\frac{ n }{40}\, cm .\) The value of \(n\) is\(....\)
- A \(50\)
- B \(55\)
- C \(60\)
- D \(62\)
Answer & Solution
Correct Answer
(A) \(50\)
Step-by-step Solution
Detailed explanation
Final image at \(\infty\) \(\Rightarrow\) obj. for eye piece at \(5 cm\) \(\Rightarrow\) image for objective at \(5 cm\) \(\frac{1}{v}-\frac{1}{u}=\frac{1}{f}\) \(\frac{1}{5}+\frac{1}{x}=1\) \(\frac{1}{x}=1-\frac{1}{5}=\frac{4}{5} \Rightarrow x=\frac{5}{4}\)
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