Q.
A glass prism ABC (refractive index 1.5), immersed in water (refractive index 4/3). A ray of light is incident normally on face $AB$. If it is totally reflected at face $AC$ then
A) $\sin{\theta \geq \frac{8}{9}}$
B) $\sin{\theta \geq \frac{2}{3}}$
C) $\sin{\theta = \frac{\sqrt{3}}{2}}$
D) ${\frac{2}{3} < \sin}{\theta < \frac{8}{9}}$
Explanation
(a) For total internal reflection at $AC$ face
$\sin{i \geq \frac{\mu_{w}}{u_{g}}}$
$\sin{\theta \geq \frac{4}{3 \times 1.5}}$
$\sin{\theta \geq \frac{8}{9}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.