MHT CET20227 Aug 2022Morning ShiftPhysicsElectromagnetic InductionActual
A metal rod of length ' 1 ' rotates about one of its ends in a plane perpendicular to a magnetic field of induction ' B '. If the e.m.f. induced between the ends of the rod is ' e ' then the number of revolutions made by the rod per second is
Options
- A^2 eB
- Be B ^2
- Ce B ^2 l
- DB ^2 e
Correct answer
B. e B ^2
Step-by-step solution
The induced emf e = d dt = d dt ( AB )= B dA dt In one rotation the rod traces out a circle of radius 1 or an area A = l ^2 So, in n rotations it will trace out an area of n l^2 aligned & e = B A t = B n l ^2 t & But n t = No.of rev.performed time = frequency f & e = Bf l ^2= Bf.A & f = e B l ^2 aligned