Alternating Current

Assertion : A capacitor of suitable capacitance can be used in an AC circuit in place of the choke coil. Reason : A capacitor blocks DC and allows AC only.

In LCR series circuit, source voltage is $120 \mathrm{~V}$ and voltage across inductor $50 \mathrm{~V}$. If voltage drop across resistance is $40 \mathrm{~V}$, then determine voltage in capacitor.

In a $L C R$ oscillatory circuit, find the energy stored in inductor at resonance if voltage of source is $10 \mathrm{~V}$, resistance is $10 \Omega$ and inductance $=1 \mathrm{H}$.

In a transformer number of turns in primary circuit is 500 and in secondary circuit number of turns is 10 . The load resistance is $10 \Omega$ and voltage of secondary coil is $50 \mathrm{~V}$. Then find the current in…

A series combination of resistor $(R)$ and capacitor $(C)$ is connected to an AC source of angular frequency $\omega$. Keeping the voltage same, if the frequency is changed to $\frac{\omega}{3}$, the current becomes…

An electric bulb has a rated power of $50 \mathrm{~W}$ at $100 \mathrm{~V}$. If it is used on an AC source of $200 \mathrm{~V}$, $50 \mathrm{~Hz}$, a choke has to be used in series with it. This choke should have an…

A transformer with efficiency $80 \%$ works at $4 \mathrm{~kW}$ and $100 \mathrm{~V}$. If the secondary voltage is $200 \mathrm{~V}$, then the primary and secondary currents are respectively

In an $L C R$ circuit as shown in figure, both switches are open initially. Now switch $S_1$ is closed, $S_2$ kept open. ($q$ is charge on the capacitor and $\tau=R C$ is capacitive time constant). Which of the…

Assertion : At resonance, $L C R$ series circuit have a minimum current. Reason : At resonance, in LCR series circuit, the current and e.m.f are not in phase with each other.

A series resonant $L C R$ circuit has a quality factor (Q-factor) 0.4 . If $R=2 \mathrm{k} \Omega, C=0.1 \mu \mathrm{F}$, then the value of inductance is

A coil of inductance $8 \mu \mathrm{H}$ is connected to a capacitor of capacitance $0.02 \mu \mathrm{F}$. To what wavelength is this circuit tuned?

An inductive circuit contains a resistance of $10 \Omega$ and an inductance of $2 \mathrm{H}$. If an $\mathrm{AC}$ voltage of $120 \mathrm{~V}$ and frequency $60 \mathrm{~Hz}$ is applied to this circuit, the current…