## What is normal on light?

At the point of incidence where the ray strikes the mirror, a line can be drawn perpendicular to the surface of the mirror. This line is known as a normal line (labeled N in the diagram). The normal line divides the angle between the incident ray and the reflected ray into two equal angles.

## What is the 2 laws of reflection?

Laws of reflection are: (i) The incident ray, the reflected ray and the normal ray at the point of incidence, lie in the same plane. (ii) The angle of incidence is equal to the angle of reflection.

3rd century

## How did they make mirrors in the old days?

The earliest manufactured mirrors were pieces of polished stone such as obsidian, a naturally occurring volcanic glass. Mirrors of polished copper were crafted in Mesopotamia from 4000 BC, and in ancient Egypt from around 3000 BC. Polished stone mirrors from Central and South America date from around 2000 BC onwards.

## Why are there mirrors behind bars?

Mirrors were put up behind the bar, so that anyone enjoying a quiet drink would know if and when someone was approaching from behind them. It basically let you see if you were about to be shot in the back of the head. A mirror makes the liquor area look fuller: What’s better than a bottle of alcohol?

## Why silver is used in coating of mirrors?

Metals are the most commonly used mirror coatings. Because of their reflectivity, layers of aluminum and silver are often used. Silver is the most reflective across the visible spectrum, reflecting 95 percent of light. Aluminum is slightly less reflective yet still can reflect 90 percent of light.

## Why do bars have brass rails?

It’s generally the area where servers go to pick up their drinks and helps prevent people standing or moving their stools to sit in front of it.

## What type of glass are mirrors made of?

Mirrors are usually made with standard flat glass sheets, sometimes called float glass, but this can also be used to make windows. Laminated glass consists of two or three layers of glass bound with resin or Polyvinyl Butyral. If the glass is broken, the resin keeps it in place.