Bar moving in a magnetic field.

[DannyBoy27]

I have attached a copy of the question I am having issues with, I can't seem to figure out the equation I have to use to solve this. My lecturer did an example of this but for some reason I can't find it anywhere.

 

[Simon Bridge]

If you cannot figure out the equation - use physics instead, and derive the equation.
What is happening, mechanically and electrically, in the problem?
What sort of law will apply here?

 

[DannyBoy27]

I think I solved the problem. Emf = BLV. And we know that emf will be equal to IR when the current is 0.5A.

0.5 x 9 = 4 x 1.2 x V

Therefore the velocity equals 0.9375 m/s.

Is this correct?

 

[Simon Bridge]

Compare with:
http://farside.ph.utexas.edu/teaching/302l/lectures/node88.html
... I suspect that's the lesson you mislaid.

 

[rude man]

I think I solved the problem. Emf = BLV. And we know that emf will be equal to IR when the current is 0.5A.

0.5 x 9 = 4 x 1.2 x V

Therefore the velocity equals 0.9375 m/s.

Is this correct?

Yes.
Good.
Using Blv works even when Maxwell's equations don't!