A monochromatic ray of light enters a glass slab (n = 1.5) along the normal to the surface. The angle of deviation of the refracted ray is

Question

A monochromatic ray of light enters a glass slab (n = 1.5) along the normal to the surface. The angle of deviation of the refracted ray is (A) 90° (B) 45° (C) 30° (D) 0°

Tardigrade Admin · Accepted Answer

Ray of light enters the glass slab (n = 1.5) normally, so, angle of incident, i = 0° Let angle of refraction be r. Using Snell's law n1 : sin i = n2 sin r ....(i) Here, n1 = 1, n2 = θc = 1.5 ∴ 1 sin 0° = (1.5) sin r or sin : r = 0 or r = 0°

Q. A monochromatic ray of light enters a glass slab (n = 1.5) along the normal to the surface. The angle of deviation of the refracted ray is

$9 0^{\circ}$

$4 5^{\circ}$

$3 0^{\circ}$

$0^{\circ}$

Ray of light enters the glass slab $(n = 1.5)$
normally, so, angle of incident, $i = 0^{\circ}$
Let angle of refraction be r.
Using Snell's law
$n_{1} sin i = n_{2} sin r$ ....(i)
Here, $n_{1} = 1, n_{2} = θ_{c} = 1.5$
$∴ 1 sin 0^{\circ} = (1.5) sin r$
or $sin r = 0$
or $r = 0^{\circ}$