- #1

cadmus

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## Homework Statement

A hollow cylinder of length L and radius R, is madeout of a non-conducting material, is charged with a constant surface charge σ, and is rotating, along its axis of symmetry, with an angular velocity w(t) = αt.

Q:What is the magnetic field inside the cylinder?

## Homework Equations

Maxwell correction for Ampere law.

## The Attempt at a Solution

The answer in the manual is B = μαtRσ

Where μ is ofcurse μ zero. [ the magnetic constant ].

The manual's solution makes perfect sense if I knew that the circular electric field which is induced by the fact that the magnetic field is changing in time is constant.

because then i could say that that the

**displacement current density is zero.**

Q: How can derive that the circular electric field, induced by the changing -in-time magnetic field, is not changing with time?

Thanks in advance