Question

Figure shows an incident ray ‘AO' and the normal 'ON'on a plane mirror. The angle which
the incident ray 'AO' makes with the mirror is 30°.
(a)
Find the angle of incidence.
(b)
Draw the reflected ray and then find the angle between the incident and reflected
ray.​

Answer 1

Answer:

a) The angle between the incident and reflected ray = angle of incidence + angle of reflection 

Since angle of incidence = angle of reflection. 

Therefore , angle between the reflected ray and the incidence ray = 60∘+60∘=120∘ 

b)

i=(90o−70o)=20o

∴r=20o

So, angle between incident ray and reflectected ray = (20o+20o)=40o

Answer 2

Answer:

(a) since NO (normal) is perpendicular to the mirror, it will make 90°with the mirror

so,

30°+ angle AON =90°

angle AON = 90-30

=60°

(b) since angle AON is 60°, angle NOB is 60°( angle of incidence= angle of reflection)

angle between incident ray and reflected ray is equal to the sum of angle of incidence and the angle of reflection

= angle AON+angle NOB

= 60°+60°

=120°