Question

A fish is a little away below the surface of a table. If the critical angle is ${49}^o$, then the fish could see things above the water surface within an angular angle of

• A. $\theta ={49}^o$
• B. $\theta ={90}^o$
• C. $\theta ={98}^o$
• D. $\theta ={24.5}^o$

Answer 1

The correct option is C $\theta ={98}^o$

Critical angle = Angle that the light ray in one side will make with the water surface

This angle will be equal to half the range in which the fish can see

$⟹$ Angle range $=2\times$ Critical angle

$=2\times 49={98}^0$

Hence The angular range in which the fish can see above water surface will be ${98}^0$