JEE Mains · Physics · STD 12 - 9. Ray optics and optical instruments
What is the position and nature of image formed by lens combination shown in figure? (\(f_1, f_2\) are focal lengths)
- A \(70\, cm\) from point \(B\) at left; virtual
- B \(40\, cm\) from point \(B\) at right; real
- C \(\frac{20}{3}\, cm\) from point \(B\) at right; real
- D \(70\, cm\) from point \(B\) at right ; real
Answer & Solution
Correct Answer
(D) \(70\, cm\) from point \(B\) at right ; real
Step-by-step Solution
Detailed explanation
Image by convex lens: \(\frac{1}{v} - \frac{1}{u} = \frac{1}{f}\) ; \(\frac{1}{v} + \frac{1}{{20}} = \frac{1}{5}\) \({v=\frac{20}{3}\, \mathrm{cm}}\) Image by concave lens: \(u=\left[\frac{20}{3}-2\right]=\frac{14}{3} \,\mathrm{cm}\) \(\frac{1}{v}-\frac{1}{u}=\frac{1}{f}\) ;…
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