Question

The figure shows an L-shaped rod rotating about its
end O in a plane perpendicular to a magnetic field
B. The part OA of rod is non conducting while AB is
conducting the emf induced between A and B is?
​

Answer 1

Answer:

Explanation:

A rod of length l rotates with a uniform angular velocity ω rad/s about an axis passing through its middle point but normal to its length in a uniform magnetic field of induction B with its direction parallel to the axis of rotation. The induced emf between the two ends of the rod is :

 

 

 

 

 

November 22, 2019avatar

Navya Katthal

ANSWER

Note that an EMF always generated along the direction (  

V

×  

B

)

For circular motion,    

V

=  

R

ω

Hence, EMF induced, ε=ω(  

R

×  

B

)

Now, the two halves of the rod equal, OA=OB  

thus, ∣  

R  

1

​  

 

​  

∣=∣  

R  

2

​  

 

​  

∣

but  

R  

1

​  

 

​  

=−  

R  

2

​  

 

​  

.

Therefore, the induced EMFs will be in the opposite direction from the point O.

Thus two EMFs ε  

1

​  

 and ε  

2

​  

 are generated in equal and opposite direction, leading to a net ZERO potential difference across

the ends.