A concave lens of focal length 20cm is placed in contact with a plane mirror will act as - Physics - Ray Optics and Optical Instruments

Question

A concave lens of focal length 20cm is placed in contact with a
plane mirror will act as?

Pintu B. · Accepted Answer

Dear Student ,
It will act as a concave mirror of focal length 10 cm
1F=2f+1fmHere ,fm=∞So , F=f2=202=10 cm
Regards

A concave lens of focal length 20cm is placed in contact with a plane mirror will act as?