**Short Questions**

- Why do we prefer a choke coil to rheostat in an a.c. current?
- What is meant buy independence of an a.c. current?
- Why is choke coil preferable to resistor?
- Why is choke considered superior to a rheostat?
- What do you mean by r.m.s value of an AC current?
- What is meant by wattles current?
- Fluorescent tubes often use an inductor to limit the current through the tube. Why is it better to use inductor than a resistor for this purpose?
- Why is a choke coil better than a resistor ina n electrical appliences?
- Define rms value of alternating current.
- What are the advantages of a.c. over d.c.?
- A chock coil is preferred to a resistor in an ac current. Why?

**Long Questions**

- Discuss the phase relationship between the voltage and current in the ac current containing inductance and resistance. What is power factor of the circuit?
- Find the impendence of LCR circuit in series.
- An alternating emf is applied across a capacitor. Show that the current in its leads to the applied emf by 90°.
- An a.c. passes through a circuit containing a resistor and a inductor in series. Derive an expression for the phase relation between the current and the voltage.
- Discuss the phase relationship between the voltage and current in the a.c. circuit containing capacitor and resistor in series and hence derive an expression for the impedance of the circuit.
- Derive the condition for resonant frequency of an LCR alternating current series circuit.
- Derive an expression of current flowing through a.c. circuit containing a resistor and capacitor in series combination. What is the power factor of this circuit?
- Discuss the phase relationship between the circuit and voltage in a.c. circuit containing capacitor and resistor in series and hence derive an expression for the impedance of the circuit.

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