Question

a beaker is filled with water to a height of 12.5 cm . the apparent depth of the needle is 9.4 cm . what is the refractive index of water? is a liquid of the needle is 1.63 is used instead of water , find the apparent depth of the needle.

Answer 1

Actual depth of the needle in water (h1) = 12.5 cm

Apparent depth of the needle in water (h2) = 9.4 cm

Refractive index of water = μ

The value of μ can be obtained

μ = h1/ h2 = 12.5/9.4 = 1.33

Hence, the refractive index of water is about 1.33.

Water is replaced by a liquid of refractive index (μ1) = 1.63

The actual depth of the needle remains the same, but its apparent depth changes. Let y be the new apparent depth of the needle.

Hence,

μ1 = h1/y

y = h1/μ1

   = 12.5/1.63 = 7.67 cm

Distance by which the microscope should be moved up = 9.4 – 7.67 = 1.73 cm