Question

A 8.10cm diameter wire coil is initially oriented so that its plane is perpendicular to a magnetic field of 0.710T pointing up. During the course of 0.120s, the field is changed to one of 0.240T pointing down. What is the average induced emf in the coil?

Answer 1

The average induced emf in the coil is 20.19 mV

Step-by-step 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.

`E.M.F= (\delta \phi)/(dt) = (BA)/(t)`

where;

A is the area of the wire = ¹/₄ (πd²)

= ¹/₄ (π x 0.081²) = 0.005154 m²

`E.M.F = ((0.71-0.24)*0.0053)/(0.12) =0.02019 \ V = \ 20.19 \ mV`

Therefore, the average induced emf in the coil is 20.19 mV