Class 10 Science

# Reflection of Light

The bouncing back of rays of light from a polished and shiny surface is called reflection or reflection of light. It is similar to bouncing back of a football after colliding with a wall or any hard surface.

These notes are based on the chapter Light: Reflection and Refraction from class 10 science NCERT book and CBSE syllabus

• Laws of reflection of light
• Types of image
• Image formation in plain mirror

## Laws of Reflection of light

Fig: Reflection of Light

• The angle of incidence and angle of reflection is equal.
• The incident ray, reflected ray and normal to the point of reflection lie in the same plane.

The angle of incidence is denoted by ∠i and angle of reflection is denoted by ∠r. The law of reflection is applicable to all types of reflecting surface.

### Mirror and Reflection of Light

Mirror is a shiny polished object (glass) which reflects most of the rays of light falling upon it. One side of mirror is polished with suitable material to make the other side reflective.

## Types of Image

Real Image: Image which is formed in front of the mirror and can be obtained on a screen is called real image.

Virtual Image: Image which is formed behind the mirror and cannot be obtained on a screen is called virtual image.

## Types of Mirror

There are two types of mirror, viz. plain mirror and spherical mirror. A mirror having a flat surface is called plane mirror. A spherical mirror has a curved surface.

## Formation of image in plane mirror

Fig: Image formation in plain mirror

This figure shows a plain mirror. A (on LHS of plain mirror) is the object. A' (on RHS of plain mirror) is the image. Solid lines show real rays of light. Dashed lines show virtual rays of light.

• A plane mirror always forms virtual and erect image.
• The distance of image and that of object is equal from the mirror.
• The image formed by a plane mirror is laterally inverted.

## Types of Reflection

### Regular Reflection

Laws of reflection are obeyed in every codition. When light is reflected from a perfectly smooth surface, all the reflected rays are parallel to each other. This condition is called regular reflection. In other words, when all the reflected rays are parallel to each other, the reflection is called regular reflection.

Clear image is formed in case of regular reflection. That is why, we are able to see clear image in a plain mirror.

### Irregular Reflection

When light is reflected from a rough surface, the reflected rays are not parallel to each other. Such a condition is called irregular reflection. In other words, when reflected rays are not parallel to each other, the reflection is called irregular reflection.

Blurred image is formed in case of irregular reflection. That is why we are not able to see clear image in pond water or on a metal plate. Degree of clarity of blurriness of image depends on extent of roughness or smoothness of a reflecting surface. No surface in nature is smooth. So, we get to see somewhat diffused images in most of the cases.

More from this Lesson