FIGURE 23-8
-A bar magnet with its south pole pointing toward a coil of wire of cross-sectional area 0.020 m² and seven turns is thrust into the coil as shown in Figure 23-8(b) . If the rate of change in the strength of the magnetic field caused by the motion of the bar magnet is 0.040 T/s, what is the magnitude of the induced emf in that coil of wire?

Question

FIGURE 23-8

-A bar magnet with its south pole pointing toward a coil of wire of cross-sectional area 0.020 m² and seven turns is thrust into the coil as shown in Figure 23-8(b) . If the rate of change in the strength of the magnetic field caused by the motion of the bar magnet is 0.040 T/s, what is the magnitude of the induced emf in that coil of wire?

Quizplus · Accepted Answer

The magnitude of the induced emf is given by the equation:emf = -N * (dΦ/dt)where:N is the number of turns in the coildΦ/dt is the rate of change in the magnetic flux through the coilIn this case, we have:N = 7dΦ/dt = 0.040 T/sA = 0.020 m^2The magnetic flux through the coil is given by the equation:Φ = BAwhere:B is the magnetic field strengthA is the cross-sectional area of the coilThe rate of change in the magnetic flux through the coil is given by the equation:dΦ/dt = B * (dA/dt) + A * (dB/dt)In this case, we have:dA/dt = 0dB/dt = 0.040 T/sTherefore, the magnitude of the induced emf is:emf = -N * (dΦ/dt)= -7 * (0.020 m^2) * (0.040 T/s)= -5.6 × 10^-3 VTherefore, the correct answer is A.

FIGURE 23-8 -A Bar Magnet with Its South Pole Pointing Toward a Pointing