A rod of length 60 cm rotates with a uniform angular velocity 20rads−1 about its perpendicular bisector, in a uniform magnetic field 0.5 T. The direction of magnetic field is parallel to the axis of rotation. The potential difference between the two ends of the rod is ____ V.
Answer: 0
Solution
The rod rotates about its own perpendicular bisector (its midpoint), so each half of the rod is itself a rod of length L/2 rotating about one of its own ends, generating the same motional EMF, in the same rotational sense, from the centre to each tip. By symmetry, the potential at both ends is equal to the potential at the centre, so