Question

The magnification of a convex mirror is +0.55✕ for objects 2.2 m from the mirror. What is the focal length of this mirror?

Answer 1

magnification M = 0.55
object u = 2.2 m
magnification M = v/u
v = Mu
= 0.55*2.2
= 1.21 m
focal length of convex mirror 1/f = 1/v-1/u
                                                      = (1/1.21)-(1/2.2)
                                                      = 0.826-0.45
                                                      = 0.376
focal length of mirror f = 1/0.376
= 2.65 m.

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