A convex mirror with a focal length of -20 cm forms an image 15 cm behind the surface.If the object height is 1.2 cm what is the image height?

Question

Quizplus · Accepted Answer

The image height is 0.30 cm. This can be calculated using the thin lens equation: 1/f = 1/do + 1/di, where f is the focal length, do is the object distance, and di is the image distance. In this case, f = -20 cm, do = -35 cm (since the object is 15 cm behind the surface), and di = -15 cm. Substituting these values into the equation, we get: 1/-20 = 1/-35 + 1/-15, which simplifies to: -1/20 = -2/35, which further simplifies to: di = -15 cm. The image height is then given by: hi/ho = -di/do, where hi is the image height and ho is the object height. In this case, ho = 1.2 cm and di = -15 cm, so: hi/1.2 = -(-15)/(-35), which simplifies to: hi = 0.30 cm.

A Convex Mirror with a Focal Length of -20 Cm