In a frame S, there are two stationary objects A & B at a distance L in the x-direction. Object A is nearer to the observer than object B. Light will take time T to reach object B from A. Therefore in frame S,(adsbygoogle = window.adsbygoogle || []).push({});

L/T = c

In another frame S’, both objects A & B are moving at velocity v in positive x-direction with respect to the observer. Therefore in frame S’, the distance between object A & B will be :

L’ = L/(gamma)

and the time for light to reach object B from A will be:

T’ = T(gamma)

An observer in frame S’ will observe that the total distance travelled by light in reaching object B from A will be:

L’ +v(T’)

Also, the time taken by light to reach object B from A will be: T’

Thus, an observer in frame S’ will calculate the speed of light to be:

[L’ + v(T’)]/T’ = (L’/T’) + v

= [c/(gamma)^2] + v

Thus, in frame S’, the speed of light will not be c. How?

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# Variable speed of light

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