A candle is placed on the principal axis of a concave mirror at a distance of 20 cm from the mirror the focal length of the mirror is 10cm the image formed will be?

Answer 1

Real inverted and enlarged

Answer 2

Use 1/s + 1/s' = 1/f

s = 20cm

f = +10cm (positive since the mirror is concave)

1/s'=1/f - 1/s

1/s'=1/10 - 1/20 = 1/20

So, s'=20cm. The distance from the image to the mirror is 20cm, which is not surprising, since the object placed at 1/2 of the focal length and therefore exactly at the radius of curvature point. The image is real and inverted.