Answer:
a) 42.52°
b) 63.98°
Explanation:
Refractive index of pipe = 1.48 = n₂
Refractive index of air = 1.0003 = n₁
[tex]\theta_r=sin^{-1}\frac{n_1}{n_2}\\\Rightarrow \theta_r=sin^{-1}\frac{1.0003}{1.48}\\\Rightarrow \theta_r=sin^{-1}0.676\\\Rightarrow \theta_r=42.52^{\circ}[/tex]
∴ Minimum angle of incidence is 42.52°
Refractive index of water = 1.33 = n₁
[tex]\theta_r=sin^{-1}\frac{n_1}{n_2}\\\Rightarrow \theta_r=sin^{-1}\frac{1.33}{1.48}\\\Rightarrow \theta_r=sin^{-1}0.899\\\Rightarrow \theta_r=63.98^{\circ}[/tex]
∴ Minimum angle of incidence is 63.98°
