[amp_mcq option1=”Resistances provide the only opposition to current flow” option2=”Capacitive reactance provides the only opposition to current flow” option3=”The ac voltage leads the current by 90 degree” option4=”Combinations of resistance and capacitive reactance provide any opposition to current flow E. None of the above” correct=”option2″]
The correct answer is: B. Capacitive reactance provides the only opposition to current flow.
A purely capacitive circuit is a circuit that contains only capacitance and no resistance. In such a circuit, the current leads the voltage by 90 degrees. This is because the capacitor stores charge, and the current is the rate at which the charge is stored. The higher the frequency of the AC voltage, the greater the capacitive reactance and the smaller the current.
Option A is incorrect because resistance does not provide the only opposition to current flow in a purely capacitive circuit. Capacitive reactance also provides opposition to current flow.
Option C is incorrect because the AC voltage does not lead the current by 90 degrees in a purely resistive circuit. In a purely resistive circuit, the current and voltage are in phase.
Option D is incorrect because resistance and capacitive reactance do not provide any opposition to current flow in a purely capacitive circuit. In a purely capacitive circuit, only capacitive reactance provides opposition to current flow.
Option E is incorrect because the statement in option B is the only one that accurately describes a purely capacitive circuit.