AC curnt Quiz Practice Quiz | AC Curnt

Q: In a purely capacitive AC circuit, what is the phase relationship between the voltage and current?

Current leads voltage by 90 degrees. — Capacitors store energy. Current changes before voltage. Hence, current leads.

Q: What is the form factor of a sinusoidal AC waveform?

1.11 — Form factor = RMS value / Average value. For a sine wave, it is approximately 1.11.

Q: What is the relationship between peak-to-peak voltage (Vpp) and RMS voltage (Vrms) in a sinusoidal AC waveform?

Vrms = Vpp / (2 * ?2) — Vrms = Vpeak / ?2 and Vpp = 2 * Vpeak. Therefore, Vrms = Vpp / (2 * ?2).

Q: In an RLC series AC circuit, at resonance, what is the impedance of the circuit?

Equal to the resistance (R). — At resonance, XL = XC, and they cancel out. Impedance is minimum and equals R.

Q: What is the main advantage of using AC over DC for power transmission over long distances?

AC is easier to step up or step down in voltage. — Transformers can efficiently change AC voltage levels, minimizing transmission losses.

Q: The power factor in an AC circuit is defined as:

The ratio of true power to apparent power. — Power factor = True Power / Apparent Power = cos(?), where ? is phase angle.

Q: What is the effect of increasing the frequency of the AC supply on the impedance of an inductor?

Impedance increases. — Inductive reactance (XL) = 2 * pi * f * L. Hence, increasing f increases XL.

Q: What is the unit of reactive power?

Volt-Ampere Reactive (VAR) — Reactive power measures energy stored/released in reactive components; units are VARs.

Q: In a series RLC circuit, if the inductive reactance (XL) is greater than the capacitive reactance (XC), the circuit behaves as:

Inductive. — XL > XC implies a net inductive effect, as inductor impedance dominates.

Q: Which of the following is NOT a property of a sinusoidal AC waveform?

It has a constant amplitude. — Amplitude varies in sinusoidal form. It is not constant.

Question 1 of 10

In a purely capacitive AC circuit, what is the phase relationship between the voltage and current?

Capacitors store energy. Current changes before voltage. Hence, current leads.

Question 2 of 10

What is the form factor of a sinusoidal AC waveform?

Form factor = RMS value / Average value. For a sine wave, it is approximately 1.11.

Question 3 of 10

What is the relationship between peak-to-peak voltage (Vpp) and RMS voltage (Vrms) in a sinusoidal AC waveform?

Vrms = Vpeak / ?2 and Vpp = 2 * Vpeak. Therefore, Vrms = Vpp / (2 * ?2).

Question 4 of 10

In an RLC series AC circuit, at resonance, what is the impedance of the circuit?

At resonance, XL = XC, and they cancel out. Impedance is minimum and equals R.

Question 5 of 10

What is the main advantage of using AC over DC for power transmission over long distances?

Transformers can efficiently change AC voltage levels, minimizing transmission losses.

Question 6 of 10

The power factor in an AC circuit is defined as:

Power factor = True Power / Apparent Power = cos(?), where ? is phase angle.

Question 7 of 10

What is the effect of increasing the frequency of the AC supply on the impedance of an inductor?

Inductive reactance (XL) = 2 * pi * f * L. Hence, increasing f increases XL.

Question 8 of 10

What is the unit of reactive power?

Reactive power measures energy stored/released in reactive components; units are VARs.

Question 9 of 10

In a series RLC circuit, if the inductive reactance (XL) is greater than the capacitive reactance (XC), the circuit behaves as:

XL > XC implies a net inductive effect, as inductor impedance dominates.

Question 10 of 10

Which of the following is NOT a property of a sinusoidal AC waveform?

Amplitude varies in sinusoidal form. It is not constant.

AC curnt Quiz