Chapter 16.1, Problem 8SSC

To determine

The evidence that light travels in a straight line.

Explanation of Solution

Introduction:

Light has speed is $3\times {10}^8\text{m/s}$ .There are so many shreds of evidence from which we can assure that light travels in a straight line. For example, it can be easily seen that light travels in a linear path from the phenomena of a shadow, scattering, absorption, etc.

If a body blocks light from a source, then it creates a shadow which is an area which is dark. The shape of the object that obstructs the light defines the shadow’s shape. On the other hand, from the scattering of light, it can be easily seen that light travels in a straight line.

In the case of scattering, many objects present in the atmosphere possess the ability to disperse light beams. Light beams are scattered in every direction. For certain cases, the dispersal occurs from extremely large particles in the air (such as particles of dust). For other instances, the scattering is thought to be due to interactions between the incident light and airborne molecules.

In the case of absorption, many objects present in the atmosphere possess the capacity to absorb light beams.

Conclusion:

Hence, some of the evidence of light travelling in a straight line are shadow, scattering of light, absorption.etc