Re: [Phys-l] induced electric field

["LaMontagne, Bob" <RLAMONT@providence.edu>]

My response at bottom.

________________________________________
From: phys-l-bounces@carnot.physics.buffalo.edu [phys-l-bounces@carnot.physics.buffalo.edu] On Behalf Of John Denker [jsd@av8n.com]
Sent: Wednesday, November 18, 2009 12:06 AM
To: Forum for Physics Educators
Subject: Re: [Phys-l] induced electric field

On 11/17/2009 11:08 AM, Philip Keller wrote:
> Thank you for the reply -- I will need to read this all more slowly.
> But for now, I hope this is an easy question.  What happens to an
> isolated point charge in a region in space with a uniformly
> increasing uniform mag field?  Does it experience a force?

Sure.

> If so, in what direction?

In the same direction as the E field.  F = q E.
For ordinary not-too-weird-shaped regions, the
field will be azimuthal, i.e. in the dθ direction.

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Where is the axis of this azimuth? If the region of dB/dt is very large an symmetric, I don't see how there is a specific direction for E. You could integrate curl E around a path to get an "EMF" , but how do actually identify E or its direction at a particular point?

Bob at PC