Induced emf in a rotating conductor

[FRANCLI]

Homework Statement

Find the induced emf in a rotating disc of radius (a) in a magnetic field (B), rotating with uniform angular velocity (w). If the disc is replaced by a rotating conductor of length (a) fixed at one end find the induced emf in the conductor.

2. The attempt at a solution
For the rotating disc:
Subistituting in the expresion :
de = B*v*dr
where v=w*r
and integrating from 0 to a
the result was:
E=(B*w*a*a)/2 volts.
But what about the rotating conductor ?? will i subistitute in the same above expression??
and if so,, I will end up with the same result!
Is the induced emf is the same for a rotating conductor and a rotating disc?

Please help.

 

[berkeman]

Homework Statement

Find the induced emf in a rotating disc of radius (a) in a magnetic field (B), rotating with uniform angular velocity (w). If the disc is replaced by a rotating conductor of length (a) fixed at one end find the induced emf in the conductor.

2. The attempt at a solution
For the rotating disc:
Subistituting in the expresion :
de = B*v*dr
where v=w*r
and integrating from 0 to a
the result was:
E=(B*w*a*a)/2 volts.
But what about the rotating conductor ?? will i subistitute in the same above expression??
and if so,, I will end up with the same result!
Is the induced emf is the same for a rotating conductor and a rotating disc?

Please help.

What do they mean by a "rotating conductor"? I don't understand that -- is there a figure that goes with this question?

If the "conductor" is bent into the shape of the circumference of the disk, then yes, it should be the same. If the conductor is just a straight wire, where it the return path for the current?

 

[FRANCLI]

there is no figure.
this problem was in other language and i translated it to English and i mistranslated the word conductor,, i think they mean a bar or a rod,,
PS: you can get the current using carbon brushes.