Question

A strong electromagnet produces a uniform magnetic field of 1.60 T over a cross-sectional area of 0.340 m2. A coil having 190 turns and a total resistance of 16.0 Ω is placed around the electromagnet. The current in the electromagnet is then smoothly reduced until it reaches zero in 20.0 ms. What is the current induced in the coil?

Answer 1

Answer:

i = 323 A

Explanation:

Initial flux due to magnetic field from the coil is given as

$\phi = NB.A$

here we will have

$N = 190$

$B = 1.60 T$

$A = 0.340 m^2$

now the flux is given as

$\phi_1 = (190)(1.60)(0.340) = 103.36 T m^2$

finally current in the electromagnet changed to zero

so final flux in the coil is zero

$\phi_2 = 0$

now we know that rate of change in flux will induce EMF in the coil

so we will have

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

$EMF = \frac{103.36 - 0}{20 \times 10^{-3}}$

$EMF = 5168 Volts$

now induced current is given as

$i = \frac{EMF}{R}$

$i = \frac{5168}{16} = 323 A$