Lineman Electrical Theory and Principles 3

Question 1

In a balanced three-phase system, what is the phase angle difference between each phase?

Accepted Answer

120 degrees

Answer

90 degrees

Answer

180 degrees

Answer

60 degrees

Question 2

What is the line voltage in a three-phase wye (Y) system if the phase voltage is 7,200V?

Accepted Answer

12,470V

Answer

7,200V

Answer

10,182V

Answer

14,400V

Question 3

Capacitive reactance (XC) in an AC circuit behaves how as frequency increases?

Accepted Answer

Decreases inversely

Answer

Increases proportionally

Answer

Remains constant

Answer

Doubles with each octave

Question 4

Faraday's Law of Electromagnetic Induction states that the induced EMF in a conductor is proportional to:

Accepted Answer

The rate of change of magnetic flux through the circuit

Answer

The resistance of the conductor

Answer

The total current flowing in adjacent conductors

Answer

The capacitance of the nearby components

Question 5

In AC power systems, what does the term 'impedance' represent?

Accepted Answer

The combined opposition to AC current including resistance and reactance

Answer

Only the resistive opposition to current flow

Answer

Only the reactive opposition from inductors and capacitors

Answer

The ratio of voltage to frequency in the circuit

Question 6

When two conductors carry current in opposite directions, the magnetic fields between them:

Accepted Answer

Add together, strengthening the field between the conductors

Answer

Cancel each other, reducing the field between the conductors

Answer

Rotate at the supply frequency

Answer

Have no interaction with each other

Question 7

What is the primary purpose of a neutral conductor in a single-phase electrical system?

Accepted Answer

To provide a return path for unbalanced current

Answer

To carry fault current to ground during a short circuit

Answer

To increase the voltage capacity of the system

Answer

To measure the power factor of the load