Light of wavelength 5000 mathringA falls on a plane reflecting surface. For what angle of incidence is the reflected ray normal to the incident ray?

Question

Light of wavelength 5000 mathringA falls on a plane reflecting surface. For what angle of incidence is the reflected ray normal to the incident ray? (A) 0° (B) 30° (C) 90° (D) 45°

Tardigrade Admin · Accepted Answer

Reflected ray is normal to the incident ray, ∴ i+r=90° As r=i ∴ 2 i=90° ⇒ i=(90°/2)=45°

Q. Light of wavelength $5000 \overset{˚}{A}$ falls on a plane reflecting surface. For what angle of incidence is the reflected ray normal to the incident ray?

$0^{\circ}$

$3 0^{\circ}$

$9 0^{\circ}$

$4 5^{\circ}$

Reflected ray is normal to the incident ray,
$∴ i + r = 9 0^{\circ}$
As $r = i$
$∴ 2 i = 9 0^{\circ}$
$\Rightarrow i = \frac{9 0 ^{\circ}}{2} = 4 5^{\circ}$

Q. Light of wavelength 5000A˚ falls on a plane reflecting surface. For what angle of incidence is the reflected ray normal to the incident ray?

0∘

30∘

90∘

45∘