Question

The depth of pond is 20 m. What is the apparent depth for a person looking normally to the water surface meu w =4 /3

Answer 1

Refractive index of water = 4/3 = Real depth/Apparent depth
Real depth = Apparent depth + 2.7 m

4/3 = (Apparent depth + 2.7 m)/Apparent depth
= 1 + 2.7/Apparent depth
Or

1/3 = 2.7/ Apparent depth

⇒ Apparent depth = 2.7 x 3 = 8.1 m

Real depth = Apparent depth + 2.7 m

= 8.1 + 2.7

= 10.8 m