Question

In the diagram shown, an object O is at a distance 10 cm above the water level. Water column in beaker is of 12 cm which is kept on a plane
mirror. If refractive index of water is 4/3 then the distance D behind the mirror where the image
I is formed is?


1. 16 cm
2. 22 cm
3. 19 cm
4. 20 cm​

Answer 1

The distance behind the mirror is 20 cm.

Option (D) is correct.

Explanation:

D (apparent) = D (actual) / µ

D (apparent) = 10 / 4 / 3 = 10 x 3 / 4

D (apparent) = 30 / 4

D (apparent) = 7.5 cm

For the plain mirror I acts as the Object.

12 + 7.5 = 19.5 ~ 20 cm

Thus the distance behind the mirror is 20 cm.

Answer 2

Explanation:

this is the ans ..ans must be added to your copy