Question

A toy car is placed 39.0 cm from a convex mirror. The image of the car is upright but one-third as large as the actual car. Calculate the mirror\'s power in diopters.

Answer 1

Let u be the object distance and v be the image distance.

It is given that the image of the car is upright and one-third as large as the actual car.

Thus, the magnification of the convex mirror is

   m = - 1/3

v / u = -1/3

     v = -u / 3

Let f be the focal length of the convex mirror.

From mirror equation,

Substitute 39.0 cm for u in the above equation,

Now, the power of the mirror is

Therefore, the power of the convex mirror is -5.13 diopters.