what i have studied is that any change in the electric field travels in space with the speed of light....right(adsbygoogle = window.adsbygoogle || []).push({});

suppose any electric field generated by an infinite plane sheet of charge

E=[tex]\sigma[/tex]/2[tex]\epsilon[/tex]...where [tex]\sigma[/tex] is surface charge density

now suppose [tex]\sigma[/tex] is doubled instantaneously.

this results in a disturbance in electric field travelling linearly with the velocity of light

now consider a gaussian cube of edge e at a distance of (c i.e 3*10^8 m) away from plate

such that one of its face is // to the plate.

suppose its one half is outside the plane ( c distance away from charged plate)and other half on other side of it.

now E field disturbane must have reached only till one half of cube

1 second after the instant when we doubled charge density

now calculating net flux

flux through four surfaces // to EF =0

we are left with two surfaces.

one at a distance < c.......A

other > c..............B

at time one sec past the instant when we doubled charge density

flux through A will double but negative of B anyhow net flux will not come out to be 0

but isnt it against Gauss law as the cube has no charge in it

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# Speed of transfer of disturbance in E,M field

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