Why there's a reading on the voltmeter connected to coil Q?

[Asad Raza]

Homework Statement

The current in coil P is constant. An iron rod is inserted into coil P. Coil Q is placed next to P with a voltmeter connected to it. Explain why, during the time that the rod is moving, there is a reading on the voltmeter connected to coil Q

Homework Equations

emf=-Dphi/dt

The Attempt at a Solution

[/B]
I believe that the Iron rod will first be magnetised and then the magnetic lines originating from Iron will cause a change of flux in coil Q.

 

[CWatters]

Find the equation for the magnetic field produced by a coil/solenoid. What does it depend on? What is changing in this set up?

 

[Asad Raza]

Find the equation for the magnetic field produced by a coil/solenoid. What does it depend on? What is changing in this set up?

The equation is B=uIn, and none of the u and n are constant. Current is changing due to change of flux inside the coil P as Iron screens the magnetic lines of P?

 

[CWatters]

The number of turns n is constant, as is the length l.

What do you know about the relative permeability u?

 

[CWatters]

PS it's nothing to do with "screening".

 

[rude man]

PS it's nothing to do with "screening".

Nope.
Reconsider post 2. Diligently.