Question

A wire 88cm long bent into circular loop is placed perpendicular to the magnetic field of density 2.5wbm^-2 within 0.5s the loop is changed into 22cm square and flux density is increased to 3.0wbm^-2 .calculate the value of induced emf

Answer 1

Length of the circular loop

$L = 88 cm$

$2\pi R = 88$

$R = 14 cm$

now area of the loop is given by

$A = \pi r^2 = 616 cm^2$

initial magnetic flux will be given by

$\phi_1 = B.A = 0.0616 * 2.5 = 0.154 Wb$

now when it is convert to square loop

area of the loop will be

$A = L^2 = 0.22 * 0.22 = 0.0484 m^2$

now final magnetic flux will be

$\phi_2 = 0.0484* 3 = 0.1452 Wb$

Now as per Faraday's law EMF induced is given by

$EMF = \frac{\phi_2 - \phi_1}{\Delta t}$

$EMF = \frac{0.154 - 0.1452}{0.5}$

$EMF = 0.0176 Volts$

So the induced EMF will be 0.0176 volts

Answer 2

A wire 88cm long bent into circular loop is placed perpendicular to the magnetic field of density 2.5wbm^-2 within 0.5s the loop is changed into 22cm square and flux density is increased to 3.0wbm^-2. The value of induced emf is ☞ 0.0176V