Question

A 149-turn circular coil of radius 2.45 cm is immersed in a uniform magnetic field that is perpendicular to the plane of the coil. During 0.141 s the magnetic field strength increases from 50.9 mT to 98.1 mT. Find the magnitude of the average EMF, in millivolts, that is induced in the coil during this time interval.

Answer 1

94.05 mV

Explanation:

N = Number of turns = 149

r = Radius of coil = 2.45 cm = 0.0245 m

t = Time = 0.141 s

Initial magnetic field = 50.9 mT

Final magnetic field = 98.1 mT

A = Area = πr² = π×0.0245²

`\text{Induced emf}=NA(dB)/(dt)\\\Rightarrow \text{Induced emf}=149* \pi * 0.0245^2((98.1-50.9)* 10^(-3))/(0.141)\\\Rightarrow \text{Induced emf}=0.09405 V = 94.05 mV`

∴ Magnitude of the average EMF, that is induced in the coil during this time interval is 94.05 mV