A plane mirror is a flat, smooth surface that reflects light uniformly. Unlike curved mirrors, which can distort images, plane mirrors create reflections that are the same size as the object being reflected. Common examples include the mirrors in your bathroom or bedroom. 

When light hits a plane mirror, it follows a simple rule called the Law of Reflection. This law has two main parts:

1. Angle of Incidence: The angle at which the incoming light ray strikes the mirror.

2. Angle of Reflection: The angle at which the light ray bounces off the mirror.

According to the Law of Reflection, these two angles are always equal. This means that if light hits the mirror at a 30-degree angle, it will reflect off the mirror at the same 30-degree angle.

The Process of Reflection 

1. Incident Ray: This is the ray of light that travels towards the mirror.

2. Point of Incidence: This is the exact spot where the incident ray hits the mirror.

3. Normal Line: This is an imaginary line that is perpendicular (at a 90-degree angle) to the surface of the mirror at the point of incidence.

4. Reflected Ray: This is the ray of light that bounces off the mirror.

The angles formed between the incident ray and the normal line (angle of incidence) and the reflected ray and the normal line (angle of reflection) are always equal.

When light reflects off a plane mirror, it creates an image that appears to be behind the mirror. This happens because our brains trace the reflected rays back in a straight line, creating the illusion that the image is coming from behind the mirror. This is known as a virtual image because it cannot be projected onto a screen; it only appears to exist behind the mirror.

Characteristics of Images in Plane Mirrors

• Size: The image is the same size as the object.

• Orientation: The image is laterally inverted, meaning it is reversed from left to right.

• Distance: The image appears to be the same distance behind the mirror as the object is in front of it.

• Virtual: The image cannot be captured on a screen because it only appears to be behind the mirror.

1. Everyday Use: We use mirrors daily for personal grooming, applying makeup, or checking our appearance. Plane mirrors provide a clear and accurate reflection, making them ideal for these purposes.

2. Optical Instruments: Plane mirrors are used in various optical devices, such as periscopes and microscopes, to direct light and create clear images.

3. Decor and Design: Mirrors are often used in interior design to make spaces look larger and brighter by reflecting light and creating the illusion of depth.

Here’s a simple experiment to see the reflection of light in action:

1. Materials Needed: A flashlight, a small plane mirror, and a dark room.

2. Procedure: Shine the flashlight at the mirror at an angle and observe the reflected light beam. Move the flashlight and change the angle of incidence, noting how the angle of reflection changes correspondingly. You can also place an object in front of the mirror and see how its image appears behind the mirror, maintaining the same size and distance.

A kaleidoscope uses plane mirrors to create beautiful patterns. Inside a kaleidoscope, multiple plane mirrors are arranged at angles to each other. When you look through the kaleidoscope, light reflecting off the mirrors creates repeating patterns that are both symmetrical and mesmerizing.