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## Physics / Light and Sight

### Physics / Light and Sight

The branch of physics dealing with the properties and behaviour of light is called optics. Light is a form of energy which helps us to see the objects.

• Have you ever wondered why we are able to see the different objects around us or see their images in a mirror or in a pond? This is simply due to reflection of light.
• Why is the word "ambulance" written backwards in ambulance car? This is due to lateral inversion -The phenomenon due to which the left side of an object appears to be right side of the object in its image in a reflecting medium (mirror) and vice-versa is called lateral inversion.
• Enjoy interesting trivia related to spherical mirrors(concave and convex) and plane mirror, optics, sunlight. Learn about the formation of rainbow. Do you know that you can see a rainbow only when your back is towards the sun ?
• When light travels obliquely from one transparent medium into another it gets bent. e.g. This bending of light is called refraction of light. The straw appears to break at the surface of the water due to refraction of light.
As light passes from air to water, its speed slows down and the light rays are bent.
• Speed of light is different in different optical mediums.
• Refractive Index is a characteristic property of a medium. The refracting ability of a medium is measured by its refractive index. Those with higher values of refractive index are optically denser than those with lower values of refractive index. e.g. water is optically denser than air but optically rarer than glass.
• Learn about lenses - concave and convex and their image formation. Solve the problems related to lens, their image formation and refraction.
• Learn the dispersion of white light through a prism and how a spectrum is formed.
The phenomenon of splitting of white light by a prism into its constituent colours is known as dispersion.
• The band of colours obtained on a screen on passing white light through a prism, is called spectrum. Do you know why we cannot see the whole spectrum ?
• Learn about different optical instruments- simple microscope, astronomical telescope.

Exercises
Topics
Exercises
Topics
• ### Light Rays - SmartTest

SmartTest on Light Rays

• Questions: 10

### Reflection of light - SmartTest

SmartTest on Reflection of light

• Questions: 10

### Refraction of light - SmartTest

SmartTest on Refraction of light

• Questions: 10

### Lenses - SmartTest

SmartTest on Lenses

• Questions: 10
• Light rays
• Reflection of light
• Plane mirrors
• Refraction of light
• Total internal reflection
• Lenses