Electrician Electrical Theory and Math 3

Question 1

A transformer has a primary voltage of 480V and a turns ratio of 4:1. What is the secondary voltage?

Accepted Answer

120V

Answer

Secondary voltage = Primary voltage / turns ratio = 480 / 4 = 120V.

Question 2

What is the formula for calculating the area of a circle (used for conduit fill calculations)?

Accepted Answer

A = πr²

Answer

The area of a circle is π times the radius squared (A = πr²), which is essential for conduit fill calculations.

Question 3

If a circuit has apparent power of 5 kVA and true power of 4 kW, what is the power factor?

Accepted Answer

0.8

Answer

Power factor = True power / Apparent power = 4 kW / 5 kVA = 0.8.

Question 4

What does Kirchhoff's Current Law (KCL) state?

Accepted Answer

The sum of all currents entering a node equals the sum leaving it

Answer

KCL states that the algebraic sum of all currents entering and exiting a node must equal zero.

Question 5

What is the reactance of a capacitor called?

Accepted Answer

Capacitive reactance

Answer

The opposition a capacitor provides to AC current is called capacitive reactance (Xc), measured in ohms.

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