Question:
What is the speed of light in free space?
A3.5 ×10⁸ m/s
B3 ×10⁸ m/s
C3 ×10⁹ m/s
D3.5 ×10⁹ m/s
Answer:
B. 3 ×10⁸ m/s
Explanation:
Speed of light:
The speed of light is dependent on the refractive index of the medium it is travelling in.
The higher the refractive index of the medium, the lower is the speed of light.
Hence, the speed of light in a medium is inversely proportional to the refractive index of the medium in which it is travelling through.
The denser a medium, the more is its refractive index and thus, the lesser is the speed of light.
The speed of light is thus minimum in solids as they are denser and will be maximum in a vacuum as a vacuum is the least dense medium.
Speed of light in free space / air is 3 ×10⁸ m/s