Question

a ray is incident on a mirror at a glancing angle 2g. find the angle of deviation

Answer 1

Glancing angle is nothing but, the angle between incident ray and the surface of the mirror,

The angle between incident ray and normal ray + the glancing angle = 90°,

let the angle of incidence be I,
and angle of reflection be R ,

The glancing angle = 90-I

the angle of deviation + angle of incidence + angle of reflection = 180°,

We know I = R,

now angle of deviation = 180-2i,

we see that angle of deviation = 2*glancing angle,
according to data, glancing angle = 2g,.
so now the deviation angle = 2*(2g)

So the answer is 4g !

Answer 2

Answer:

180-4g

Explanation:

The angle between plane mirror and incident or reflected ray is called glancing angle

Glancing angle of incidence is 90-i

Glancing angle of reflection is 90-r

Given glancing angle is 2g

Then we know angle i= angle r

Then 180-2g-2g=α

α=180-4g

Is the angle of deviation