The capacitive reactance of a capacitor
Correct answer: B. decreases as the frequency increases
- A. increases as the frequency increases
- B. decreases as the frequency increases
- C. is independent of frequency
- D. is the same as resistance
Explanation
Reactance is one over 2 pi f C, so a capacitor passes high frequencies readily and blocks direct current entirely, since at zero frequency the reactance is infinite. This is why capacitors are used to couple audio signals while blocking any DC bias. An inductor behaves in the opposite way, opposing high frequencies most.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About AC Through Resistor, Capacitor and Inductor
Alternating current through a resistor, capacitor and inductor involves phase relationships between voltage and current, reactance, impedance and energy transfer. A resistor keeps voltage and current in phase, while a capacitor and inductor produce opposite phase shifts, a distinction used in circuit diagrams and numerical calculations.
Practise Alternating Current
592 free Alternating Current MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More AC Through Resistor, Capacitor and Inductor questions
In a purely capacitive AC circuit, the current
In a purely resistive AC circuit, the current and the voltage are
The inductive reactance of a coil is given by
The average power dissipated in a purely inductive or purely capacitive AC circuit over a complete cycle is
In a series RLC circuit at resonance
The power factor of an AC circuit is defined as