A) 24 cm
B) 10 cm
C) 15 cm
D) 120 cm
Correct Answer: C
Solution :
The focal length of the tens \[\frac{1}{f}=(\mu -1)\left[ \frac{1}{{{R}_{1}}}-\frac{1}{{{R}_{2}}} \right]\] \[\frac{1}{f}=(1.5-1)\left( \frac{1}{20}-\frac{1}{30} \right)\] \[\frac{1}{f}=0.5\left( \frac{30-20}{600} \right)\] \[\frac{1}{f}=\frac{1}{2}\times \frac{10}{600}=\frac{1}{120}cm\] or \[f=120cm\]You need to login to perform this action.
You will be redirected in
3 sec