A normally incident ray reflected at an angle of 90° . The value of critical angle is:

Question

A normally incident ray reflected at an angle of 90° . The value of critical angle is: (A) 45° (B) 90° (C) 65° (D) 43.2°

Tardigrade Admin · Accepted Answer

Critical angle C is equal to incident angle if ray reflected normally ∴ C =90° if- i) C >90° then TIR takes place ii) C ≤ 90° then no TIR takes place.

Q. A normally incident ray reflected at an angle of $9 0^{\circ} .$ The value of critical angle is:

$4 5^{\circ}$

$9 0^{\circ}$

$6 5^{\circ}$

$43. 2^{\circ}$

Critical angle $C$ is equal to incident angle if ray reflected normally
$∴ C = 9 0^{\circ}$ if-
i) $C > 9 0^{\circ}$ then TIR takes place
ii) $C \leq 9 0^{\circ}$ then no TIR takes place.

Q. A normally incident ray reflected at an angle of 90∘. The value of critical angle is:

45∘

90∘

65∘

43.2∘