Question

A convex mirror has focal lenght of 15 cm. An object is placed at 20 cm from the pole of this lens. Predict the nature of the image formed.

Answer 1

A minor correction: it is the radius of curvature, not culture. f = R/2 = 30 cm.

Convention: negative Di indicates VIRTUAL image and the (f) of a convex mirror is, by convention, NEGATIVE (as is the f of all diverging optical elements).

Using the mirror formula: - 1/30 = 1/15 + 1/Di → Di = - 10 cm. The image therefore is virtual, diminished, 2/3 the size of the object, ERECT and inside the mirror.