A) 80cm
B) 40cm
C) 20cm
D) 160cm
Correct Answer: B
Solution :
Focal length of the combination lens, \[\frac{1}{f}=\frac{1}{{{f}_{1}}}+\frac{1}{{{f}_{2}}}=\frac{1}{40}+\frac{1}{40}\] \[\therefore \] \[f=20cm\] Given, \[m=1\] \[m=\frac{f}{u-f}\] \[1=\frac{20}{u-20}\] \[u-20=20\] \[u=40cm\]You need to login to perform this action.
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