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

Answer

B, C, D

Explanation

Height of the lake =2.5 m
When the sun is just setting q is approximately =900
`:. (sini)/(sinr)=mu_2/mu_1`
`rarr 1/(sinr)=(4/3)/1`
`rarr sinr=3/4 rarr r=49^@`
Thus (x/2.5)=tanr=1.15`
`rarr x=2.5xx1.15=2.8m`