NTA Abhyas JEE Main2020PhysicsElectromagnetic InductionPractice
A conducting ring of radius r and resistance R is placed in a region of uniform time varying magnetic field B which is perpendicular to the plane of the ring. If the magnetic field is changing at a rate α , then the current induced in the ring is
Options
- Aπ r 2 α 2 R
- B2 π r α R
- Cπ r α R
- Dπ r 2 α R
Correct answer
D. π r 2 α R
Step-by-step solution
The magnitude of the induced emf in the ring is ε = d ϕ d t = d d t B A = A d B d t = π r 2 α The induced current in the ring, I = ε R = π r 2 α R