Question

The speed of light in vacuum is:
1. 3 × 10¹⁰ m / s 
2. 3 × 108 m / s 
3. 2 × 108 m / s 
4. 2.25 × 10⁸ m / s

Answer 1

Correct Answer - Option 2 : 3 × 108 m / s 

The correct answer is 3 × 108 m / s.

• Light
  • Light is a form of energy that makes us see.
  • An object reflects the light that falls on it.
  • This reflected light when received by our eyes enables us to see the object.
  • The speed of light in a vacuum or the air is 3 x 108 m / s and it is different in different media.
  • Light travels in a straight line.
  • The speed and wavelength of light change when it travels from one medium to another but frequency remain unchanged.

 

Speed of light in some common media

Medium	Speed of Light
Vacuum	3*108 m/s
Water	2.25*108 m/s
Glass	2*108 m/s
Rock Salt	1.96*108 m/s
Nylon	1.96*108 m/s