Question

When a wire loop is rotated in a magnetic field, the direction of induced emf change by?

Answer 1

Magnetic Field:

The action of magnetism on moving electric charges, electric currents, and magnetic materials is explained by a magnetic field, which is a vector field. A moving charge is subjected to a force in a magnetic field that is perpendicular to both its own velocity and the magnetic field.

Magnetic Flux:

Magnetic flux is the number of magnetic field lines that pass through a closed surface. It calculates the total magnetic field that flows through a given area.

The flux of the magnetic field through the loop

$\mathrm{\varphi }=\mathrm{B}.\mathrm{Acos\omega t}$

Where,

• $\mathrm{\varphi }$ is the magnetic flux.
• $\mathrm{B}$ is the magnetic field
• $\mathrm{A}$ is the area
• $\mathrm{\omega t}$ the angle at which the field lines pass through the given surface area

When an electrical conductor is put into a magnetic field, emf is induced in it as a result of the dynamic interaction between the conductor and the magnetic field.

$$\begin{gathered} \mathrm{Emf}=-\frac{\mathrm{dt}}{\mathrm{d\varphi }} \\ =\mathrm{B}.\mathrm{A\omega sin\omega t} \end{gathered}$$

$$\begin{gathered} \mathrm{\omega t}=0\mathrm{to}\mathrm{\pi },\mathrm{sin\omega t}=+\mathrm{ve} \\ \mathrm{\omega t}=\mathrm{\pi }\mathrm{to}2\mathrm{\pi },\mathrm{sin\omega t}=-\mathrm{ve} \end{gathered}$$

Hence, the direction of induced e.m.f. changes once in$\frac{1}{2}$​ revolution.