A wave has velocity u in medium P and velocity 2u in medium Q. If the wave is refracted from medium P to medium Q at an angle of incidence 30° , then the angle of refraction will be

Question

A wave has velocity u in medium P and velocity 2u in medium Q. If the wave is refracted from medium P to medium Q at an angle of incidence 30° , then the angle of refraction will be (A) 30°  (B) 45°  (C) 60°  (D) 90°

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="Solution" src="https://cdn.tardigrade.in/q/nta/p-h3ynobkk8jnr.png" /> From Snell's law, μ P sin 30o = μ Q sin r sin r = (μ P/μ Q) sin 30o as μ propto (1/v) sin r = (2 u/u) (1/2) = 1 r = 90o

Q. A wave has velocity $u$ in medium $P$ and velocity $2 u$ in medium $Q .$ If the wave is refracted from medium $P$ to medium $Q$ at an angle of incidence $3 0^{\circ},$ then the angle of refraction will be

$3 0^{\circ}$

$4 5^{\circ}$

$6 0^{\circ}$

$9 0^{\circ}$

From Snell's law,
$μ_{P} s in 3 0^{o} = μ_{Q} s in r$
$s in r = \frac{μ _{P}}{μ _{Q}} s in 3 0^{o}$
as $μ \propto \frac{1}{v}$
$s in r = \frac{2 u}{u} \frac{1}{2} = 1$
$r = 9 0^{o}$

Q. A wave has velocity u in medium P and velocity 2u in medium Q. If the wave is refracted from medium P to medium Q at an angle of incidence 30∘, then the angle of refraction will be

30∘

45∘

60∘

90∘