An object is 50 cm from a concave mirror of radius of curvature of magnitude 60 cm. How far is the image from the mirror?
A) 75 cm
B) 19 cm
C) 120 cm
D) 35 cm
E) 60 cm

Question

Quizplus · Accepted Answer

The mirror equation is 1/f = 1/v + 1/u, where f is the focal length, v is the image distance, and u is the object distance. For a concave mirror, the focal length f is negative and equals -R/2, where R is the radius of curvature. Here, f = -60/2 = -30 cm. The object distance u is -50 cm (negative because it's on the same side as the light source). Plugging these values into the mirror equation gives 1/-30 = 1/v + 1/-50. Solving for v gives v = 75 cm, which means the image is 75 cm from the mirror on the same side as the object (hence, it's a real image).

An Object Is 50 Cm from a Concave Mirror of Radius