Home » Ask Physics » Light, Time and Vacuum

Subscribe to Blog via Email

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 3,066 other subscribers

Archives

Light, Time and Vacuum

Share with:


Why does the light needs time to travel through vacuum?Is there something makes it needs time? How did we prove that  there is nothing in vacuum?

Answer:

When there is no medium, there is nothing to oppose the propagation of light and therefore it moves with a constant velocity. All electromagnetic waves including light travel in vacuum with the same velocity (3 x 10^8 m/s). Since the energy is to travel from one point to another, a finite time is also required.

English: Electromagnetic waves can be imagined...

The velocity of light is experimentally determined by many different methods. (Romer’s methos, Fizau’s method, Foucault’s method, Michelson’s method etc.)

When light travels in a medium, whenever light interacts with the matter, the atoms absorb light and are re – emitted and the average speed in a medium will be less than in vacuum. In vacuum, there is no matter t interact and that’s why there light travels with maximum velocity.

(If you remember the structure of atom, most of the space inside an atom is vacuum. The speed of light decreases only when it encounters matter. So, when we consider a particular medium, the speed of light is a constant in it)

Ask a Doubt

Post your Physics Doubts here

Name (required)

Email (required)

Subject

Message/Doubt/Question

Upload a file if required

askphysics@Twitter

Half Yearly Exam Count Down

Half Yearly Exam Count Down KVS Ernakulam RegionOctober 17th, 2017
The Half Yearly Examination for Kendriya Vidyalayas of Kerala starts from 17 October 2017
%d bloggers like this: