A) 1.25 cm
B) 2.5 cm
C) 1.05 cm
D) 2 cm
Correct Answer: B
Solution :
[b] Convex lens will form image \[{{I}_{1}}\] at its focus which acts like a virtual object for concave lens. Hence, for concave lens,\[u=+4cm\], \[f=20\]cm. so by lens formula \[\frac{1}{-20}=\frac{1}{v}-\frac{1}{4}\Rightarrow v=5cm\] i.e., distance of final image \[({{I}_{2}})\]from concave lens v=5 cm by using \[\frac{v}{u}=\frac{I}{O}\Rightarrow \frac{5}{4}=\frac{I}{2}\Rightarrow ({{I}_{2}})=2.5cm\]You need to login to perform this action.
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