Question

Two parallel plane mirrors m1 and m2 have length of 20m each and are 10cm apart .a ray of light is incident on one end of mirror m2 at an angle of 53 . calculate the the number of times the ray undergoes reflection after light emerges out of the system

Answer 1

Answer:

Light will come out after N = 150 reflections

Explanation:

As per law of reflection we know that the angle of reflection = angle of incidence

now we know that light ray incident on the mirror at an angle of 53 degree so it will strike the other mirror at a distance "d"

now we have

\frac{d}{w} = tan 53

w

d

=tan53

here we know that

w = 10 cm

now we have

\frac{d}{10 cm} = \frac{4}{3}

10cm

d

=

3

4

d = 13.3 cmd=13.3cm

so after every 13.3 cm it will strike either mirror for reflection

so total number of reflections are given as

N = \frac{20 \times 100}{40/3}N=

40/3

20×100

N = 150N=150