Answer:
The average induced emf in the coil is 20.19 mV
Explanation:
Given;
diameter of wire, d = 8.10cm = 0.081 m
initial magnetic field strength, B₁ = 0.71 T
final magnetic field strength , B₂= 0.24 T
time = 0.12 s
According to Faraday's law, average induced emf in the coil is directly proportional to the rate of change of flux.
[tex]E.M.F= \frac{\delta \phi}{dt} = \frac{BA}{t}[/tex]
where;
A is the area of the wire = ¹/₄ (πd²)
= ¹/₄ (π x 0.081²) = 0.005154 m²
[tex]E.M.F = \frac{(0.71-0.24)*0.0053}{0.12} =0.02019 \ V = \ 20.19 \ mV[/tex]
Therefore, the average induced emf in the coil is 20.19 mV
