Assertion: Power loss in ideal choke coil is zero.

Reason: Ideal choke coil has zero resistance.

Assertion: The average power loss in series $LC$ circuit is always zero.

Reason: The average values of voltage and current in A.C. is zero.

Assertion : Capacitor serves as a block for D.C.and offers an easy path to A.C. 
Reason : Capacitive reactance is inversely proportional to frequency

Assertion: Choke coil is preferred over a resistor to adjust current in an AC circuit.

Reason: Power factor for inductance is zero. So, power loss is also zero.

Assertion: In series $RL$ AC circuit, voltage leads the current.

Reason: In series $RC$ AC circuit, current leads the voltage.

Assertion: An alternating current of frequency $50 \mathrm{Hz}$ becomes zero, $100$ times in one second.

Reason: Alternating current changes direction and becomes zero twice in a cycle.