Consider the infinite ladder circuit shown below:

For which angular frequency $\omega$ will the circuit behave like a pure inductance?

In the circuit shown, the switch is closed at time $t=0$

Which of the graphs shown below best represents the voltage across the inductor, as seen on an oscilloscope?

A rectangular loop of wire shown below is coplanar with a long wire carrying current $I$.

The loop is pulled to the right as indicated. What are the directions of the induced current in the loop and the magnetic forces on the left and the right sides of the loop?

A conducting rod of mass $m$ and length $l$ is free to move without friction on two parallel long conducting rails, as shown below. There is a resistance $R$ across the the rails. In the entire space around, there is a uniform magnetic field $B$ normal to the plane of the rod and rails. The rod is given an impulsive velocity $v_0$.

Finally, the initial energy $\frac{1}{2}m{v}_0^2$.

A blackbox $\left(\mathrm{BB}\right)$ which may contain a combination of electrical circuit elements (resistor, capacitor or inductor) is connected with other external circuit elements as shown below in the figure $\left(\mathrm{a}\right)$. After the switch $\left(S\right)$ is closed at time $t=0$, the current $\left(I\right)$ as a function of time $\left(t\right)$ is shown in the figure $\left(\mathrm{b}\right)$.

From this we can infer that the blackbox contains

The figure shows a bar magnet and a metallic coil. Consider four situations. 

$\left(\mathrm{I}\right)$ Moving the magnet away from the coil.
$\left(\mathrm{II}\right)$ Moving the coil towards the magnet.
$\left(\mathrm{III}\right)$ Rotating the coil about the vertical diameter.
$\left(\mathrm{IV}\right)$ Rotating the coil about its axis.
An emf in the coil will be generated for the following situations.

An ac voltmeter connected between points $A$ and $B$ in the circuit below reads $36 \mathrm{V}$. If it is connected between $A$ and $C$, the reading is $39 \mathrm{V}$. The reading when it is connected between $B$ and is $D$ $25 \mathrm{V}$. What will the voltmeter read when it is connected between $A$ and $D?$) Assume that the voltmeter reads true rms voltage values and that the source generated a pure ac.)