Discuss the types of $AC$ generator. How much power they deliver? What is the frequency of $AC$ generator?

An electron is moving in a circular orbit of radius $R$ with an angular acceleration $\alpha$. At the centre of the orbit is kept a conducting loop of radius $r$ $(r \ll R)$. The $e.m.f.$ induced in the smaller loop due to the motion of the electron is

$A$ circular insulated copper wire loop is twisted to form two loops of area $A$ and $2A$ as shown in the figure. At the point of crossing,the wires remain electrically insulated from each other. The entire loop lies in the plane of the paper. $A$ uniform magnetic field $\vec{B}$ points into the plane of the paper. At $t=0$,the loop starts rotating about the common diameter as an axis with a constant angular velocity $\omega$ in the magnetic field. Which of the following options is/are correct?
[$A$] The rate of change of the flux is maximum when the plane of the loops is perpendicular to the plane of the paper.
[$B$] The net emf induced due to both the loops is proportional to $\cos \omega t$.
[$C$] The emf induced in the loop is proportional to the sum of the areas of the two loops.
[$D$] The amplitude of the maximum net emf induced due to both the loops is equal to the amplitude of maximum emf induced in the smaller loop alone.

$A$ coil is placed in a magnetic field of $1 \, T$. Its area changes at a rate of $\frac{5 \, m^2}{ms}$. If the current in the coil changes from $1 \, A$ to $2 \, A$ in $2 \times 10^{-3} \, s$,what is the inductance of the coil in $H$?

$A$ coil of wire having finite inductance and resistance has a conducting ring placed coaxially within it. The coil is connected to a battery at time $t = 0$,so that a time-dependent current $I_1(t)$ starts flowing through the coil. If $I_2(t)$ is the current induced in the ring and $B(t)$ is the magnetic field at the axis of the coil due to $I_1(t)$,then as a function of time $(t > 0)$,the product $I_2(t) B(t)$:

What length of wire is required to construct a solenoid of length $l_0$ and inductance $L$?