Question

A tank is filled with water to a height of 12.5 cm. The apparent depth of a needle lying at the bottom of the tank is measured by a microscope to be 9.4 cm. What is the refractive index of water? If water is replaced by a liquid of refractive index 1.63 up to the same height, by what distance would the microscope have to be moved to focus on the needle again?

Answer 1

Refer to the attachments

Apparent depth = real depth / refractive index

or

9.4 = 12.5 / μ

μ = 12.5 /9.4

μ = 1.33.

Now for the other part.

Apparent depth h' = 12.5 / μ'

h' = 12.5 /1.63

h' = 7.67

Previously apparent depth was 9.4 cm

Hence Microscope have to be moved by

= (9.4 - 7.67 )

= 1.73 cm.

Hope it helps :-)

Answer 2

Answer:

a) 1.33 cm

b) 1.73 cm

hope so this helped you