The essential difference between an AC generator and a DC generator is that

The phenomenon of electromagnetic induction has been technologically important application in the generation of alternating currents." Name the device which can generate alternating currents. Draw a neat diagram of it.

 A rectangular coil having an area vector $\overline{\mathrm{A}}$ and number of turns $\mathrm{N}$ is rotating in a magnetic field $\overline{\mathrm{B}}$ with angular speed $\omega$. If $\theta$be the angle made by the area vector $\overline{\mathrm{A}}$ with the field $\overline{\mathrm{B}}$ at time $t$. Derive an expression for alternating emf $\epsilon$ starting directly from Faraday's law. Draw a graph to show the generated e.m.f at the time   $0 ,\frac{\mathrm{T}}{4}.\frac{\mathrm{T}}{2},\frac{3\mathrm{T}}{4}\mathrm{and} \mathrm{T}$.

What is a dynamo? Describe an a.c. dynamo under the following headings:

$\left(\mathrm{ii}\right)$ Labelled diagram

In a.c. generator induced emf at $\mathrm{t}=0$. the induced emf at the time $\frac{\pi }{\omega }$ is_____________.

What is a dynamo? Describe an a.c. dynamo under the following headings:

$\left(\mathrm{iii}\right)$ Working.

With the help of a labelled diagram, derive the expression for instantaneous emf induced in an AC generator.

Briefly explain working of a.c. generator.

In a $\mathrm{DC}$ generator, brushes are made of

What converts mechanical energy to electrical energy.