The radius of curvature of a mirror is 20 cm, its focal length is : [1]
A. 20 cm
B. 10 cm
C. 40 cm
D. 5 cm
Answer:B
The radius of curvature of a mirror is 20 cm, its focal length is : [1]
A. 20 cm B. 10 cm C. 40 cm D. 5 cm