A square coil of area 70 cm² and 600 turns rotates in a magnetic field B = 0.4 T. It completes 500 revolutions per minute. Find the instantaneous emf, in volts, when the plane of the coil is inclined at 60° to the field. Take π = 22/7.
Physics · Electromagnetic Induction · Rotating coil emf
JEE Mains JEE Advanced

Question

A square coil of area 70 cm² and 600 turns rotates in a magnetic field B = 0.4 T. It completes 500 revolutions per minute. Find the instantaneous emf, in volts, when the plane of the coil is inclined at 60° to the field. Take π = 22/7.

Physics · Electromagnetic Induction · Rotating coil emf

G1 Physics · Accepted Answer

Given: N = 600 A = 70 cm² = 70 × 10⁻⁴ m² B = 0.4 T Angular speed: ω = 500 × 2π/60 = 100π/6 rad s⁻¹ If the plane is at 60° to B, the area vector is at 30° to B. Instantaneous emf magnitude: e = NABω sin 30° = 600 × 70 × 10⁻⁴ × 0.4 × (100π/6) × 1/2 Using π = 22/7: e = 44 V Final answer: 44.