Solveeit Logo
Login

Question

Question: Radius of curvature of concave mirror is 40 cm and the size of image is twice as that of object, the...

Radius of curvature of concave mirror is 40 cm and the size of image is twice as that of object, then the object distance is

A

60 cm

B

C

40 cm

D

30 cm

Answer

30 cm

Explanation

Solution

m=−2m = - 2

By using −2=−20−20−u⇒u=−30 cm- 2 = \frac { - 20 } { - 20 - u } \Rightarrow u = - 30 \mathrm {~cm}

For virtual image; m=+2m = + 2

So, +2=−20−20−u⇒u=−10 cm+ 2 = \frac { - 20 } { - 20 - u } \Rightarrow u = - 10 \mathrm {~cm}