Let us list some of the factors, which could possibly influence thespeed of wave propagation: (i) nature of the source. (ii) direction of propagation. (iii) motion of the source and/or observer. (iv) wavelength (v) intensity of the wave.On which of these factors, if any, does(a) the speed of light in vacuum,(b) the speed of light in a medium (say, glass or water),depend?

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Solution

(a)

Light is an electromagnetic radiation which belongs to visible range in electromagnetic spectrum. Visible range is the range of wavelengths of the radiation visible to human eye.

The speed of the light in vacuum is approximately 3× 10 8 m/s. This value is universal constant and the motion of source, nature of source and anything else do not affect it.

Einstein’s special theory of relativity is based on the fact that speed of light in vacuum is independent of any factor.

(b)

Dependency of the speed of light in a medium:

(i) The nature of source does not affect the speed of light. Speed of the wave depends on the properties of the medium, not on the source.

(ii) For all the isotropic mediums, the speed of light is independent in the direction of propagation.

(iii) The speed of light is independent of the motion of the source relative to the medium, but the relative motion of the observer and the medium affect the speed of light.

(iv) Light is an electromagnetic radiation which propagates in the medium as a wave, and speed of a wave depends on the wavelength, thus, speed of light depends on wavelength.

(v) The intensity of light has no effect on its speed.

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Similar questions

Let us list some of the factors, which could possibly influence the speed of wave propagation:

(i) Nature of the source.

(ii) Direction of propagation.

(iii) Motion of the source and/or observer.

(iv) Wave length.

(v) Intensity of the wave.

On which of these factors, if any, does

(a) The speed of light in vacuum,

(b) The speed of light in a medium (say, glass or water), depend?

As a wave propagates

(i)The wave intensity remains constant for a plane wave.

(ii)The wave intensity changes inversely as the square of the distance from the source for a spherical wave.

(iii) The intensity of the spherical wave or at any spherical surface centered at source remains the same at all times.

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