Question

the angle between an incident ray and the plane mirror is 30 degree. the total angle between the incident ray and reflected ray will be...​

Answer 1

i=r

so the total angle btw incident ray and reflected ray=30+30=60degree

Answer 2

Given:

Angle between plane mirror and incident ray = 30°

To find: Total angle between the incident ray and reflected ray

Calculation:

From the figure below,

• MN is the normal at point O on the plane mirror AB.
• PO is the incident ray and OQ is the reflected ray.
• ∠AOP = 30°
• ∠PON = 60° (because MN is perpendicular to AB which means ∠AON = 90°)

From laws of reflection, angle of incidence is equal to angle of reflection.

So, ∠NOQ = 60°

Therefore, total angle between the incident ray and reflected ray = ∠POQ = 120°