A) \[10cm\]
B) \[15cm\]
C) \[7.5cm\]
D) \[6.6cm\]
Correct Answer: B
Solution :
: As image is real \[\therefore \] Magnification, \[m=-\frac{v}{u}=-3\]or \[v=3u\] Here, \[u=-20\text{ }cm\] \[\therefore \] \[v=-60cm\] According to mirror formula \[\frac{1}{f}=\frac{1}{v}+\frac{1}{u}\] \[\frac{1}{f}=\frac{1}{-60}+\frac{1}{-20}=-\frac{4}{60}\] \[f=-15cm\] \[|f|=15cm\]You need to login to perform this action.
You will be redirected in
3 sec