The resonance frequency of a series LCR circuit is:

A transformer has 100 primary turns and 500 secondary turns. If primary voltage is 220 V, secondary voltage (in V) is:

In an ideal step-up transformer with $N_s > N_p$:

The term $\cos\phi$ in AC power is called:

The average power dissipated in a pure capacitor in an AC circuit is:

At resonance in a series LCR circuit, the impedance equals the resistance $R$.