JEE Main 1-Sep-2021 Shift 2 Solved Paper

Let us draw the diagram of glass tumbler.
Consider the actual height of the tumbler be H.
The refractive index of the water, μ=

4

3

The refractive index of the air, μ=1
As we know that,
μwater=

Hreal

Happearent

4

3

=

H

Happearent

⇒ Happearent=

3H

4

The height of air observed by observer = 17.5 –H
According to the above figure,

3H

4

=17.5−H
⇒ H = 10.11 cm ≃ 10 cm
The actual height of the water in tumbler is 10 cm.