Question

Refraction of light from air to glass and from air to water are shown in figure (i) and figure (ii) below. The value of the angle $\theta$ in the case of refraction as shown in figure (iii) will be

• A. ${30}^o$
• B. ${35}^o$
• C. ${60}^o$
• D. ${41}^o$

Answer 1

The correct option is

B

${35}^o$

Using Snell's law, ${}^a{u}_g=\frac{sin{60}^{\circ }}{sin{35}^{\circ }},{}^a{\mu }_w=\frac{sin{60}^{\circ }}{sin{41}^{\circ }}and{}^w{\mu }_g=\frac{sin{41}^{\circ }}{sin\theta }$

${}^a{\mu }_w\times {}^w{\mu }_g={}^q{\mu }_g$

$\Rightarrow \frac{sin{60}^{\circ }}{sin{41}^{\circ }}\times \frac{sin{41}^{\circ }}{sin\theta }=\frac{sin{60}^{\circ }}{sin{35}^{\circ }}\Rightarrow sin\theta =sin{35}^{\circ }or\theta ={35}^{\circ }$