A) 20 cm
B) 10 cm
C) 40 cm
D) 30 cm
Correct Answer: B
Solution :
Here, the point at which the beam would have converged in absence of the lens acts as virtual object. So, \[u=+20\,\,cm\]. Again since the image is inverted and of same size\[,\] \[m=-1\]. \[\therefore \] \[m=-1=\frac{v}{u}\] \[\Rightarrow \] \[v=-20\,\,cm\] \[\therefore \] \[\frac{1}{f}=\frac{1}{v}-\frac{1}{u}=\frac{1}{-20}-\frac{1}{20}=\frac{-2}{20}=\frac{-1}{10}\]You need to login to perform this action.
You will be redirected in
3 sec