Question #2c961

2 Answers
Nov 10, 2017

In the air medium,though for all lights the velocity is same so all lights reach all together.

Explanation:

But for R#->#red in V#->#I#->#B#->#G#->#Y#->#O#->#R has the largest wavelength...So it has a probability to get on earth fast than other rays...

Hope ti helps...
Thank you...

Nov 11, 2017

In vacuum all electromagnetic radiations travel at the same speed. So from the sun all light travel at the same speed until it reaches the Earth's atmosphere. Once the light reaches the atmosphere, then its speed in the atmosphere depends on its wavelength.

The ratio of the speed of light in vacuum to its speed in a medium is called the refractive index of the medium.

Refractive Index: #n \equiv c/v#
#c - "speed of light in vacuum"; \qquad v - "speed of light in medium"#

By this definition, higher the refractive index lower is the speed and vice versa.

For visible light in air the refractive index is highest for violet and lowest for red.

#1 < n("red") < n("green") < n("violet") #

This means violet travels slower than red in atmospheric air. So red reaches the Earth's surface first, followed by green and finally violet.