JEE Main20203 Sep 2020Evening ShiftPhysicsElectromagnetic InductionActual
A uniform magnetic field B exists in a direction perpendicular to the plane of a square loop made of a metal wire. The wire has a diameter of 4 mm and a total length of 30 cm . The magnetic field changes with time at a steady rate dB / dt = 0 . 032 Ts - 1 . The induced current in the loop is close to (Resistivity of the metal wire is 1 . 23 × 10 - 8 Ωm )
Options
- A0.43 A
- B0.61 A
- C0.34 A
- D0.53 A
Correct answer
B. 0.61 A
Step-by-step solution
Radius = d / 2 = 2   mm R wire = ρ l A ϕ = BA  ;  e = dϕ dt = dB dt A i = e R = dB dt A 2 ρ l = 0 . 032 × π × 2 × 10 - 3 2 1 . 23 × 10 - 8 × 4 × 0 . 3 = 0 . 61   A