A) 60 cm from the convex lens
B) 60 cm from the concave lens
C) 70 cm from the convex lens
D) 70 cm from the concave lens
Correct Answer: A
Solution :
[a] Len's formula is given by \[\frac{1}{f}=\frac{1}{v}-\frac{1}{u}\] For convex lens, \[\frac{1}{30}=\frac{1}{v}+\frac{1}{60}\]\[\Rightarrow \]\[\frac{1}{60}=\frac{1}{v}\] Similarly for concave lens \[\frac{1}{-120}=\frac{1}{v}-\frac{1}{40}\]\[\Rightarrow \]\[\frac{1}{v}=\frac{1}{60}\] Virtual object 10 cm behind plane mirror. Hence real image 10 cm infront of mirror or, 60 cm from convex lens.You need to login to perform this action.
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