A light ray inclined at an angle `30^(@)` with the horizontal falls on a plane mirror and after reflection light ray becomes vertical. At what angle the plane mirror is inclined with the horizontal?

Explanation

To solve the problem, we need to determine the angle at which the plane mirror is inclined with the horizontal when a light ray strikes it at an angle of 30 degrees and reflects vertically. Here’s a step-by-step solution:

### Step 1: Understand the Setup
We have a light ray inclined at an angle of 30 degrees with the horizontal. This means that the angle of incidence (the angle between the incoming ray and the normal to the mirror) needs to be determined based on the inclination of the mirror.

### Step 2: Define the Angle of Inclination
Let the angle of inclination of the mirror with the horizontal be denoted as θ. The normal to the mirror will then be at an angle of (90° - θ) with the horizontal.

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