# The Velocity of Light is

- 3 x 10
^{8 }cm/sec - 3 x 10
^{8}m/sec - 3 x 10
^{8 }km/sec - 3 x 10
^{8}miles/sec

**Answer: (2). 3 x 10^**8 m/ sec.

The speed of light is denoted as** ‘c’.** its value is **299 792 458 m/s** on rounding of figure value comes 3 x 10^8 m/s. it is universal physical constant. the speed of light is changed in the air or in water due to the refractive index of the mediums.

The definition of light is that the distance travelled in metre by light in vacuum during a time interval of 1 / 299, 792, 458 of a second. the speed of light first recorded discussed by Aristotle . and the first real measurement of the speed of light came about in half century in 1676, by a** Danish astronomer Ole Romer in Paris.**