Question

Find the angle of incidence of the ray shown in Fig. for which it passes through the pole, given that `MI||CP`.

Answer 1

From the figure, the ray MI is making an angle `theta` with normal IC. From law of reflection, `angleMIC=angleCIP=theta`
As `MI ||CP rArr angleMIC=angleICP= theta`
Now, CI = CP
`rArr angleCIP=angleCPI=theta`
`:.` In `Delta CIP`, all angles are equal, i.e., `3theta=180^(@)`
`rArr theta = 60^(@)`