Question

A mirror produces an image that is located 41.0 cm behind the mirror, when the object is located 6.60 cm in front of the mirror. (a) What is the focal length of the mirror? (b) Is the mirror concave or convex?

Answer 1

Image distance, v = 41 cm object distance, u = 6.60 cm (Negative sign is due to sign convection) a) focal , F = 1/f = 1/v + 1/u 1/f = 1/41 - /6.60 = 6.60 - 41/270.6 = -34.4/270.6 f = 270.6/34.4 = -7.87 cm f = -7.87 cm focal length b) If focal length f is positive it's concave mirror, f is negative it's convex mirror In th9is problem f < 0, then the given mirror is a convex mirror