Question

A concave mirror has a radius of curvature of 80cm. If the real image of an object is formed at 1m, how far from the mirror is the object?

Answer 1

66.7 cm

Step-by-step explanation:

The focal length is half the radius of curvature, or f = 40 cm.

The image is real, so i = +100 cm.

The distance to the object is therefore:

1/o + 1/f = 1/i

1/o + 1/40 = 1/100

o = -66.7 cm

The object is 66.7 cm left of the mirror.