Light Travels along a Straight Line

What are the characteristic features of light?

Name two natural phenomena based on the property that light travels in straight lines.

A small source of light casts a sharp shadow on an opaque object shows 

Name the property of light by which it always travels in straight lines.

(Choose from: Rectilinear propagation/Interference)

Most objects around us are sources of light.
 

Explain parallel light beam, convergent light beam and divergent light beam with the help of diagram.

Read the passage and answer the questions below.

We know that the white light is actually a combination of seven different colours of light. These are violet, indigo, blue, green, yellow, orange and red. All these colours together are called a natural spectrum. A natural spectrum is formed when light scatters at different wavelengths in the atmosphere. These colours are clearly visible when a rainbow is formed. So, if there are seven colours in white light, why does the sky appear mostly blue? Let us understand the reason behind this. Light travels in the form of waves. Blue light has a short wavelength and red light has a long wavelength.

An English physicist, John William Strutt Lord Rayleigh(1842-1919) explained that lights of different wavelengths get scattered when they hit the molecules of hydrogen and oxygen in the atmosphere. Owing to its shorter wavelength, the blue-coloured light gets scattered more than the red one. As such the sky appears blue.

How does light travel?

Give an activity to show that light travels in straight lines.

What is meant by rectilinear propagation of light?

Light travels in _____ lines.

Formation of shadows suggests that light travels in a

Describe an activity to show that light travels in a straight line.

_____ can travel through vacuum.

Fill in the blank with an appropriate word:

Light travels in the form of _____. (Waves/Caves/Games)