Answer:
emf = 3.2V
Explanation:
In order to calculate the magnitude of the induced emf in the coil you use the following formula:
[tex]emf=-N\frac{d\Phi_B}{dt}[/tex] (1)
N: turns of the coil = 200
ФB: magnetic flux = A*B
A: area of the coil = (0.20m)(0.40m) = 0.08m²
B: magnitude of the magnetic field
You take into account that the area of the coil is constant, while magnetic field changes on time. Then, the equation (1) becomes:
[tex]emf=-NA\frac{dB}{dt}[/tex] (2)
dB/dt = rate of change of the magnetic field = -0.20T/s (it is decreasing)
You replace the values of all parameters in the equation (2):
[tex]emf=-200(0.08m^2)(-0.20T/s)=3.2V[/tex]
The induced emf in the coil is 3.2V
