A coil of surface area 100 cm² having 50 turns is held perpendicular to a magnetic field of intensity 0.02 Wb m⁻². The resistance of the coil is 2 Ω. If it is removed from the magnetic field in 1 s, the induced charge in the coil is _.

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(4) 0.005 C. Given: A = 100 cm² = 100×10⁻⁴ = 0.01 m², N = 50, B = 0.02 T, R = 2 Ω. Idea: the charge that flows depends only on the total change of flux linkage, Q = (N |ΔΦ|)/R, not on how quickly it happens. Flux per turn at the start: BA = 0.02×0.01 = 2×10⁻⁴ Wb; after removal it is 0. Change of flux linkage: N|ΔΦ| = 50×2×10⁻⁴ = 0.01 Wb. Q = (0.01)/2 = 0.005 C (the 1 s does not enter). So the induced charge is 0.005 C.

A coil of surface area 100 cm² having 50 turns is held perpendicular to a magnetic field of intensity 0.02 Wb m⁻². The resistance of the coil is 2 Ω. If it is removed from the magnetic field in 1 s, the induced charge in the coil is _______.

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