Q17 of 123 Page 412

An object P is focused by a microscope M. A glass slab of thickness 2.1 cm is introduced between P and M. If the refractive index of the slab is 1.5, by what distance should the microscope be shifted to focus the object again?

0.70 cm

The thickness of the glass slab, d = 2 cm


and refractive index of the slab μ = 1.5


shift due to the glass slab is given by


Δ T = (1−1/μ) d = (1−1/1.5)2.1 = 0.7 cm


So, the microscope should be shifted 0.70cm to focus the object again.


More from this chapter

All 123 →
15

A pole of length 1.00 m stands half dipped in a swimming pool with water level 50.0 cm higher than the bed. The refractive index of water is 1.33 and sunlight is coming at an angle of 45° with the vertical. Find the length of the shadow of the pole on the bed.

 16

A small piece of wood is floating on the surface of a 2.5 m deep lake. Where does the shadow form on the bottom when the sun is just setting? Refractive index of water = 4/3.

 18

A vessel contains water up to a height of 20 cm and above it an oil up to another 20 cm. The refractive indices of the water and the oil are 1.33 and 1.30 respectively. Find the apparent depth of the vessel when viewed from above.

 19

Locate the image of the point P as seen by the eye in the figure (18-E5).