Question

Q3. What is the value of the unknown angle (theta) in the following diagram?
A. 30 degrees
B. 45 degrees
C. 90 degrees
D. 60 degrees
​

Answer 1

Answer:

The value of unknown angle theta would be 60 degree.

Explanation:

Let us first considered first part of light falling on mirror making angle 30 degree. Since the angle of incident is always equal to angle of reflection the angle of reflection would be 30 degree as well.

Now, the first mirror and the dotted line are parallel to each other both making 90 degree to the surface. Thus, the angle between 1st reflected ray  with surface would be 30 degree as they form alternate interior angles.

So, the 1st reflected ray act as incident ray for the 2nd mirror, thus the incident angle would also be theta. this theta and together with 30 degree forms 90 degree.

                    θ + 30⁰ = 90⁰

                    θ  = (90-30)⁰

                    θ = 60⁰

#SPJ3