Embibe Experts Solutions for Chapter: Alternating Current, Exercise 9: Exercise (Assertion & Reason)

Assertion : An alternating current is more dangerous than a direct steady current.
Reason : The frequency of the alternating current is injurious to the human body. 

Assertion :- A sinusoidal alternating current does not show any average magnetic effects.
Reason :- The average value of an alternating current is zero.

Assertion: DC and AC both can be measured by a hot wire instrument.

Reason: The hot wire instrument is based on the principle of heating effect of current.

Assertion: In a series $LCR$ circuit, the impedance is minimum at resonance.
Reason: The currents in inductance and capacitance are same and voltage out of phase at resonance in series $LCR$ circuit.

For series $RLC$ circuit, the graph between current and frequency of voltage source is shown in figure.

Assertion: Nature of circuit in region $\left(1\right)$ is capacitive while in region $\left(2\right)$ is inductive.

Reason: Power factor of circuit in region $\left(1\right)$ is negative and in region $\left(2\right)$ is positive.

Assertion: In series $LCR$ circuit, the phase difference between current and voltage is never zero.

Reason: Voltage and current are never in phase.

Assertion: A capacitor is used to minimise power loss.

Reason: A capacitor alters the phase voltage.

Assertion : In LR Circuit ohm’s law is not obeyed at every instant. 
Reason : Current always lags from voltage.