# Induced current in loop

If you have a loop that is spun clockwise as a magnet is moved near it, is a current induced in that loop?

If the loop were not spun, by Faraday & Lenz's laws a current would be generated in a direction that opposes the change in magnetic flux. Since the magnetic is moving closer and flux is increasing, in order to decrease flux current would be induced in a counter-clockwise direction (right hand rule).

Now the loop is spinning in a clock-wise direction.

One way of thought is to say that the opposing direction of the induced current and spinning loop "cancel" each other leading to a net zero current. This doesn't seem physically sound, however, since the result would then depend on your reference frame.

Further, if this were true isn't this a violation of Faraday's law — because the flux "is" still changing no matter what reference frame you take and hence there must be some induced current.

Some research tells me that this might be linked to Faraday's Paradox but I didn't quite understand the setup nor the resolution of the "paradox."

• Why would the flux change? Certainly not due to the rotation of the loop. It will change (trivially) due to the movement of the magnet. – CuriousOne Jan 24 '16 at 4:34
• @CuriousOne Yes, but if the magnetic flux changes then by faraday's law there has to be an induced current, yet the answer to this problem appears to be that there isn't. – 1110101001 Jan 24 '16 at 7:40
• The rotation of the loop doesn't change the magnetic flux trough the loop, so why would there be an induced current? There would, of course, be an induced voltage in a radial wire, so there is a radial electric field component in the rotating observer system, but that's not going to get a current going in a wire loop with constant radius. – CuriousOne Jan 24 '16 at 7:42
• @CuriousOne But in the diagram the magnet is also shown moving towards the loop. – 1110101001 Jan 24 '16 at 7:43
• And, just like I said, that movement will cause a trivial change of the flux which has absolutely nothing to do with the rotation of the wire loop... we are back to my first comment. – CuriousOne Jan 24 '16 at 7:46