You are Here: Home >< Physics

1. This is probably a pretty stupid question but I was wondering if you could help explain it. Say for example you have a magnet turning in a magnetic field at a constant rate. Why is it that an alternating current is produced? I'd have thought that if it is turning at a constant rate the rate of change of flux linkage would be constant so the result would be a DC current flowing. Why isn't this the case?
2. I am wondering if you mean coil rather than magnet?

If we are talking about a coil rotating in a field, then when the coil is vertical and the field lines are going horizontal, then the conductor is not cutting through the field lines so zero current. As the coil turns into the horizontal position, the conductor now cuts through the field lines at right angles, therefore maximum current.
3. What's the definition of a current? how is it produced? this should suffice.
4. (Original post by eswnl)
I am wondering if you mean coil rather than magnet?

If we are talking about a coil rotating in a field, then when the coil is vertical and the field lines are going horizontal, then the conductor is not cutting through the field lines so zero current. As the coil turns into the horizontal position, the conductor now cuts through the field lines at right angles, therefore maximum current.
I did mean coil, I do appologise I was quite tired when I was writing this.
5. As the rotating coil passes the north pole of a magnet a voltage is produced in a sinusoidal form which reverses as the coil passes the south pole of a magnet. Its mainly do to with the magnets polarity and the coil passing through each polarity, while the magnet is parallel to the coil no emf is induced as the electric and magnetic field lines do not cut so no current is gained. When the planes are perpendicular to the magnet an emf is induced, this is both in north and south poles which affects the direction of the current and voltage.

Hope this helps im also studying for the same exam.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: December 26, 2010
Today on TSR

Claims damages because he didn't get a first

Highest poster before midnight WINS £30!

Discussions on TSR

• Latest
• See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Discussions on TSR

• Latest
• See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.