Question

A fixed 15.3-cm-diameter wire coil is perpendicular to a magnetic field 0.77 T pointing up. In 0.20 s , the field is changed to 0.26 T pointing down. What is the average induced emf in the coil?

Answer 1

Induced emf will be 0.468 volt

Step-by-step explanation:

We have given diameter of wire d = 15.3 cm

So radius
`r=(d)/(2)=(15.3)/(2)=7.65cm`

So area
`A=\pi r^2=3.14* (7.65)^2=183.76* 10^(-4)m^2`

Change in magnetic field dB = 0.26 - 0.77 = -0.51 T

Time for change in magnetic field dt = 0.26 sec

We know that emf is given by
`e=(-d\Phi )/(dt)=-A(dB)/(dt)=-183.76* 10^(-4)* (-0.51)/(0.2)=0.0468volt`