Reflection & Refraction (C10)

An object of height 1.2 m is placed before a concave mirror of focal length 20 cm so that a real image is formed at a distance of 60 cm from it. Find the position of an object. What will be the height of the image formed?

Answer

ho = 1.2 cm

f = - 20 cm

v = - 60 cm

1/u = 1/f - 1/v

1/u = -1/20 + 1/60

u = - 30 cm

hi/ho = -v/u

hi = -60/30 × 1.2

hi = - 2.4 cm