A) 40 cm
B) 60 cm
C) 30 cm
D) 20 cm
Correct Answer: D
Solution :
The position of final image will be independent of b only when the rays are incident parallel to principal axis on concave lens, which is possible only when the object is kept at focus of palnoconvex lens. Therefore, \[\frac{1}{a}=\frac{1}{{{f}_{1}}}=(\mu -1)\left[ \frac{1}{{{R}_{1}}}-\frac{1}{{{R}_{2}}} \right]\] \[\Rightarrow \]\[\frac{1}{a}=\left( \frac{3}{2}-1 \right)\left[ \frac{1}{10}-\frac{1}{\infty } \right]\Rightarrow a=20\,cm\]You need to login to perform this action.
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