Q.

A conducting rod PQ of length l=2m is moving at a velocity v=8ms-1 making an angle 30° with its length. A uniform magnetic field B=3T exists in a direction perpendicular to the plane of motion. Then,

1 VP-VQ=49V  
2 VP-VQ=24V  
3 VQ-VP=49V  
4 VQ-VP=48V  

Ans.

(2)

ξ=Blv⊥

⇒ξ=(3)(2)(8sin30)

⇒ξ=24 V

From Fleming’s Right Hand Rule, the induced current in the rod PQ is directed from Q to B, thus giving an equivalent emf replacement of the motional emf as

So, P is at a higher potential.