Question

Explain different ways to induce the current in a coil.

Answer 1

Induced current:

1. A coil is created by conducting material forming a circular structure. When an external resistance is connected to the induced emf source, we will get induced current.
2. Induced emf is created when there is a change in magnetic flux.

Mathematically, flux can be represented as:

Magnetic flux, $\mathrm{\varphi }=\mathrm{BAcos\theta }$

Here,

$\mathrm{B}$ is the field.

$\mathrm{A}$ is the area of the loop.

$\mathrm{\theta }$ is the angle between the field and the area vector.

According to Faraday's First, induced emf,

$\begin{array}{c}\mathrm{\epsilon }=\left|\frac{\mathrm{d\varphi }}{\mathrm{dt}}\right|\\ =\left|\frac{\mathrm{d}}{\mathrm{dt}}\left(\mathrm{BAcos\theta }\right)\right|\end{array}$

According to Ohm's law, induced current,

$I=\frac{\epsilon }{R}$, where I is the current. and R is the resistance,

Different ways of creating induced current in a coil:

1. A relative movement of the bar magnet and loop will create a change in flux and hence induces current
2. If we place the loop in the time-varying field then flux will also change, so the current will induces
3. If the loop rotates in the field such that the angle of alignment of the area vector with respect to the magnetic field changes. So flux changes and hence current induces
4. If the loop moves out or into the uniform field, this will change the number of field lines passing through the loop. So current will induces.
5. Any combined effect described above can change the flux, so any of the above strategies could create a current in the loop.