Planning Lab to measure how emf varies with an angle

[rock.freak667]

A metal disc is placed in a uniform magnetic field of flux density,B,acting through the plane of the disc at and angle,\theta.When the dis is rotated an e.m.f. is induced between the centre and the rim of the disc.

http://img158.imageshack.us/my.php?image=scanlc2.jpg


Design an experiment to investigate how the induced e.m.f.,E, depends upon \theta


ok, since I am I need to measure E and \theta, I need to keep the rest constant.
\omega would be kept constant by using a motor with a constant power output to rotate the disc.

To keep B constant, use a solenoid and the field should be uniform through the centre of it. (Not sure about that)
But I do not know how to go about measuring the angle.\theta

 

[dlgoff]

"To keep B constant, use a solenoid and the field should be uniform through the centre of it. (Not sure about that)"

You would need a very large solenoid since you want B to be constant over the whole surface area of the disk. i.e A large pole-face.

"But I do not know how to go about measuring the angle..."

Just tip the magnet at a know fixed angle relative to the disk surface. Your choice.

 

[rock.freak667]

"
Just tip the magnet at a know fixed angle relative to the disk surface.

So take a protractor and just move the magnet relative to the protractor?