1 A convex mirror has a radius of 20 cm. An object is placed 30 cm in front of the mirror. Determine where the image will appear.
−45cm −55cm −6.5cm −7.5cm
Since the radius is 20 cm (which is the distance from the mirror to the centre), and since the focal point is half ways in between and negative for a convex mirror, f = -10 cm: 1/f = 1/Do + 1/Di 1/Di = 1/f - 1/Do 1/Di = 1/(-10) - 1/30 Di = -7.5 cm