NETA AC/DC Theory and Circuits 2

Question 1

In a series RLC circuit at resonance, which of the following is true?

Accepted Answer

Inductive and capacitive reactances are equal and cancel

Answer

Impedance is at its maximum value

Answer

Current is at its minimum value

Answer

Power factor equals zero

Question 2

Ohm's law states that current in a circuit is:

Accepted Answer

Directly proportional to voltage and inversely proportional to resistance

Answer

Directly proportional to resistance and inversely proportional to voltage

Answer

Equal to the product of voltage and resistance

Answer

Independent of voltage when resistance changes

Question 3

The time constant of an RC circuit is defined as:

Accepted Answer

The time for the capacitor voltage to reach 63.2% of the applied voltage

Answer

The time for the capacitor to fully charge

Answer

The time for current to reach its maximum value

Answer

The time for the capacitor to discharge to zero

Question 4

In a purely inductive AC circuit, the current:

Accepted Answer

Lags the voltage by 90 degrees

Answer

Leads the voltage by 90 degrees

Answer

Is in phase with the voltage

Answer

Leads the voltage by 45 degrees

Question 5

The effective (RMS) value of a sinusoidal AC voltage is approximately what fraction of the peak voltage?

Accepted Answer

0.707 times the peak voltage

Answer

0.5 times the peak voltage

Answer

0.637 times the peak voltage

Answer

1.414 times the peak voltage

Question 6

Power factor in an AC circuit is defined as:

Accepted Answer

The ratio of real power to apparent power

Answer

The ratio of reactive power to apparent power

Answer

The ratio of apparent power to real power

Answer

The ratio of real power to reactive power