In a convex spherical mirror, reflection of light takes place at
A) a flat-surface
B) A bent-in surface
C) a bulging-out suface
D) an even surface
Ans:- C (a bulging-out suface )
Figure explanation
If R is the radius of curvature of a spherical mirror and f is its focal length, then
A) f=R
B) f=2R
C) f=R/2 or R=2f
D) none of these
Ans-C
Explanation:- the relationship between radius of curvature and focal length is
i) focal length is half of radius of curvature
ii) radius of curvature is twice of the focal length
if the focal length of a spherical mirror is 12.5 cm, its radius of curvature will be
A) R=12.5 cm
B) R=25 cm
C) R=13 cm
D) none of these
Ans:- B
Explanation:-
Let f= focal length and Radius of curvature=R
and given the focal length of a spherical mirror is 12.5 cm
Means, f=12.5 cm
We know that
R=2f
R=2×12.5 cm
R=25 cm ans
if the focal length of a spherical mirror is 40 cm then its radius of curvature is
A) R=40 cm
B) R=20 cm
C) R=80 cm
D) none of these
Ans:- C
Explanation:-
Let f= focal length and Radius of curvature=R
and given the focal length of a spherical mirror is 40 cm
Means, f=40
We know that
R=2f
R=2×40 cm
R=80 cm ans
