COMEDK202510 May 2025Evening ShiftPhysicsElectromagnetic InductionActual
A current of 2 A is passed through the primary coil. The total flux linked with the secondary coil, which is closely wound over the primary is 2000 10⁻⁶ weber. What is the induced emf in the secondary if the current through the primary increases at a rate of 0.2 As ⁻¹ ?
Options
- A2 10⁻⁴ V
- B4 10⁻⁴ V
- C1 10⁻⁴ V
- D8 10⁻⁴ V
Correct answer
A. 2 10⁻⁴ V
Step-by-step solution
The magnetic flux linked with the secondary coil is proportional to the current I in the primary coil, given by = MI , where M is the mutual inductance between the coils. Given the flux = 2000 10⁻⁶ Wb when the current I = 2 A , we calculate the mutual inductance M as: M = I = 2000 10⁻⁶ 2 = 1000 10⁻⁶ H = 10⁻³ H The induced electromotive force (emf) e in the secondary coil is given by Faraday's law of induction, e = -M dI dt . Given the rate of change of current dI dt = 0.2 As ⁻¹ , the magnitude of the induced emf is