Question

A wire of resistance 7 ohms and length 2.8 m is bent into a circle and is concentric with a solenoid in which the magnetic flux changes from 6 T·m2 to 4 T·m2 in 0.2 seconds. What is the emf in the wire? V What is the non-Coulomb electric field in the wire? V/m What is the current in the wire?

Answer 1

Answer:

The emf, electric field and the current in the wire are 10 V, 3.57 V/m and 1.43 A.

Explanation:

Given that,

Resistance = 7 ohms

Length = 2.8 m

Time t =0.2

We need to calculate the change in magnetic flux

Using formula of induced emf

$\epsilon=\dfrac{d\phi}{dt}$

Put the value into the formula

$\epsilon=\dfrac{6-4}{0.2}$

$\epsilon=10\ V$

We need to calculate the electric field in the wire

Using formula of electric field

$E=\dfrac{V}{l}$

$E=\dfrac{10}{2.8}$

$E=3.57\ V/m$

We need to calculate the current in the wire,

Using formula of ohm's law

$V=IR$

$I=\dfrac{V}{R}$

Put the value into the formula

$I=\dfrac{10}{7}$

$I=1.43\ A$

Hence, The emf, electric field and the current in the wire are 10 V, 3.57 V/m and 1.43 A.