An LRC resonant circuit is often called an oscillator circuit. What is it that oscillates?

The counter emf in a motor is 100 V when the motor is operating at 1000 rpm. How would you change the motor's magnetic field if you wanted to reduce the counter emf to $65 ~\mathrm{V}$ when the motor was running at $2500$ rpm?

Can you tell whether the current in an LRC circuit leads or lags the applied voltage from a knowledge of the power factor, cos $\phi?$

Describe briefly how the frequency of the source emf affects the impedance of an LRC circuit far from resonance (R small).

The counter emf in a motor is 72 V when operating at 1800 rpm. What would be the counter emf at $2500$ rpm if the magnetic field is unchanged?

Describe briefly how the frequency of the source emf affects the impedance of an LRC circuit near resonance (R small).

A motor has an armature resistance of 3.75 $\Omega$. If it draws 9.20 A when running at full speed and connected to a $120$-$\mathrm{V}$ line, how large is the counter emf?

Describe briefly how the frequency of the source emf affects the impedance of a pure inductance.

If you are given a fixed length of wire, how would you shape it to obtain the greatest self-inductance? The least?

Describe briefly how the frequency of the source emf affects the impedance of a pure capacitance.

Describe briefly how the frequency of the source emf affects the impedance of a pure resistance.

A 450-loop circular armature coil with a diameter of 10.0 cm rotates at $60$ rev/s in a uniform magnetic field of strength $0.75 ~\mathrm{T}$. What is the rms voltage output of the generator? What would you do to the rotation frequency in order to double the rms voltage output?

In an LRC circuit, can the rms voltage across a capacitor, be greater than the rms voltage of the ac source? Explain.

How would you arrange two flat circular coils so that their mutual inductance was (a) greatest, (b) least (without separating them by a great distance)?