Question

An 18.5-cm-diameter loop of wire is initially oriented perpendicular to a 1.5-T magnetic field. The loop is rotated so that its plane is parallel to the field direction in 0.20 s. What is the average induced emf in the loop?

Answer 1

Answer:

The average induced emf in the loop is 0.20 V

Explanation:

Given:

Radius of loop $r = \frac{d}{2} = 9.25 \times 10^{-2}$ m

Magnetic field $B = 1.5$ T

Change in time $\Delta t = 0.20$ sec

According to the faraday's law,

Induced emf is given by

    $\epsilon = -\frac{\Delta \phi}{\Delta t}$

Where $\phi =$ magnetic flux

  $\phi = BA\cos0$                                ( here $\theta = 0$ )      

Where $A = \pi r^{2}$

We neglect minus sign because it's shows lenz law

   $\epsilon = \frac{B \pi r^{2} }{\Delta t}$

   $\epsilon = \frac{1.5 \times 3.14 \times (9.25 \times 10^{-2} )^{2} }{0.20}$

   $\epsilon = 0.20$ V

Therefore, the average induced emf in the loop is 0.20 V