MHT CET202522 Apr 2025Morning ShiftPhysicsElectromagnetic InductionActual
A coil of resistance 400 is placed in a magnetic field. If the magnetic flux ' ' (Wb) linked with the coil varies with time ' t ' (s) as =50 t^2+4 , the current in the coil at t=2 ~s will be
Options
- A1 A
- B0.5 A
- C2 A
- D0 1 ~A
Correct answer
B. 0.5 A
Step-by-step solution
The magnetic flux linkage is given by = 50t^2 + 4 Wb. Faraday's law gives the induced EMF as = - d dt = - d dt (50t^2 + 4) . The derivative is d dt = 100t , so the EMF becomes = -100t V. At time t = 2 s, we have = -100 2 = -200 V, giving a magnitude of | | = 200 V. Using Ohm's law I = | | R with R = 400 , the current is I = 200 400 = 0.5 A. Final answer: 0.5 A