Rectilinear propagation is the process by which light travels in straight lines from its source. This process is also known as rectilinear propagation of light. This phenomenon is explained by the laws of reflection and refraction. The following are the explanations of the laws of reflection and refraction.



The laws of reflection describe how light reflects off of a surface. The following are the two laws of reflection:

1. Incident ray, reflected ray, and the normal to the surface all lie in the same plane.


2. The angle of incidence is equal to the angle of reflection.

The laws of refraction describe how light bends when it passes through a medium with a different refractive index. The following are the two laws of refraction:

1. The incident ray, the refracted ray, and the normal to the surface all lie in the same plane.


2. The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant. This ratio is known as the refractive index of the medium.

When light travels through a medium with a uniform refractive index, it travels in straight lines. When it encounters a surface, it is either reflected or refracted. The laws of reflection and refraction explain how this happens.

When light is reflected, it bounces off of the surface and follows the laws of reflection. The reflected light continues to travel in straight lines.

When light is refracted, it changes direction as it passes through the surface. The amount of bending depends on the angle of incidence and the refractive index of the medium. The refracted light also follows the laws of refraction and continues to travel in straight lines.

In conclusion, rectilinear propagation is the process by which light travels in straight lines from its source. The laws of reflection and refraction explain how light behaves when it encounters a surface with a different refractive index. This process is essential in understanding the behavior of light and its interaction with different media.

To show that light travels only in a straight line .keep a candle vertically on a plane horizontal surface and light. Take a rubber tube and look through it the flame of the candle as shown in the figure The flame could be seen at the other end .Now ,bend the tube and look through it the flame of the candle . This time you cannot see the frame .This proves that light travel in straight line. Effects of rectilinear propagation of light. The effect of rectilinear propagation of light are as follows firs formation of Shadows second formation of lunar and Solar eclipse 3rd formation of images( pinhole camera)