Question

Suppose the first coil of wire illustrated in the simulation is wound around the iron core 6 times. Suppose the second coil is wound around the core N2 = 12 times. Shortly after the switch has been closed, the flux through the second coil of wire changes from 1.9 Wb per turn to 2.4 Wb in each turn of wire over a time interval of 0.2 s. Find the magnitude of the emf induced in the coil.

Answer 1

30 V

Explanation:

The induced emf, ε = -ΔΦ/Δt where ΔΦ = change in magnetic flux and Δt = time interval for change in flux.

Since we have N₂ = number of turns on second coil = 12 and initial flux per turn = 1.9 Wb per turn. The total initial flux per turn Φ₁ = 12 turns × 1.9 Wb per turn = 22.8 Wb.

Also, since we have N₂ = number of turns on second coil = 12 and final flux per turn = 2.4 Wb per turn. The total initial flux per turn Φ₂ = 12 turns × 2.4 Wb per turn = 28.8 Wb.

Since Δt = 0.2 s and the magnitude of the induced emf in the second coil, ε = ΔΦ/Δt

= (Φ₂ - Φ₁)/Δt

= (28.8 Wb - 22.8 Wb)/0.2 s

= 6.0 Wb/0.2 s

= 30 V