JEE Main 2024 Physics question
A coil is places perpendicular to a magnetic field of 5000 T. When the field is changed to 3000 T in 2 s, an induced emf of 22 V is produced in the coil. If the diameter of the coil is 0.02 m, then the number of turns in the coil is
Answer: (B)
Solution
ε = NΔ(BA)/Δt: 22 = N × 2000 × (22/7)(0.02²/4)/2, so N = 70.