Question

an object is placed at 4 cm distance from the surface of a transparent sphere made of material of refractive index 2.5 and the real image of the object is formed at the same distance from the second surface of the sphere find the diameter of the sphere​

Answer 1

Explanation:

Answer

Given: A transparent sphere of radius R and refractive index μ is kept in the air.

To find the distance from the surface of the sphere where a point should be placed so as to form a real image at the same distance from the other side of the sphere

Solution:

Using the equation,

v

μ

2

−

u

μ

1

=

R

μ

2

−μ

1

For the refraction at the first surface of the sphere,

(air to glass)

∞

μ

−

−x

1

=

R

μ−1

, Here x is the distance of point object from the sphere, as shown in above fig.

⟹

x

1

=

R

μ−1

⟹x=

μ−1

R

Hence the object should be placed this distance from the surface of the sphere in order to get real image.