Question

How far should an object be placed from the pole of converging mirror of focal length 20cm?

Answer 1

Answer:

Hope it helps you

Explanation:

f = -20cm, m = -1/4 (real image)

We know that

m = - (v/u)

-(1/4) = - (v/u)

u = 4v

so,

1/v + 1/u = 1/f

1/v + 1/4v = 1/(-20)

5/4v = - (1/20)

V = - (100/4) = -25 cm

∴ u = 4v

u = 4 × (-25)

= - 100 cm

Answer 2

Answer:

= - 100 centimetres

Explanation:

this is your answer