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

Answer:

Induced emf will be 0.468 volt

Explanation:

We have given diameter of wire d = 15.3 cm

So radius $r=\frac{d}{2}=\frac{15.3}{2}=7.65cm$

So area $A=\pi r^2=3.14\times (7.65)^2=183.76\times 10^{-4}m^2$

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 $e=\frac{-d\Phi }{dt}=-A\frac{dB}{dt}=-183.76\times 10^{-4}\times \frac{-0.51}{0.2}=0.0468volt$