Master Electrical Theory Basics: Quizzes and Practice Questions

Question 1

According to Ohm's Law, the current flowing through a circuit is directly proportional to the:

Accepted Answer

Voltage across the circuit

Answer

Resistance of the circuit

Answer

Power dissipated in the circuit

Answer

Frequency of the circuit

Question 2

Which of the following is the standard unit of resistance?

Accepted Answer

Ohm

Answer

Volt

Answer

Ampere

Answer

Coulomb

Question 3

A circuit that provides an unbroken path for current to flow is known as a:

Accepted Answer

Closed circuit

Answer

Open circuit

Answer

Short circuit

Answer

Parallel circuit

Question 4

In which type of circuit are the components connected in parallel?

Accepted Answer

Parallel circuit

Answer

Series circuit

Answer

Mixed circuit

Answer

Resonant circuit

Question 5

According to Kirchhoff's Current Law, the algebraic sum of the currents entering a junction must be:

Accepted Answer

Equal to zero

Answer

Greater than zero

Answer

Less than zero

Answer

Dependent on the voltage at the junction

Question 6

In an inductive circuit, the current:

Accepted Answer

Lags behind the voltage

Answer

Leads the voltage

Answer

Is in phase with the voltage

Answer

Is inversely proportional to the voltage

Question 7

Which of the following devices is primarily used to convert alternating current (AC) to direct current (DC)?

Accepted Answer

Diode

Answer

Transistor

Answer

Resistor

Answer

Capacitor

Question 8

In a simple series circuit, the total resistance is:

Accepted Answer

Equal to the sum of the individual resistances

Answer

Less than the sum of the individual resistances

Answer

Greater than the sum of the individual resistances

Answer

Dependent on the current flowing through the circuit

Question 9

Kirchhoff's Current Law states that in any closed circuit, the total current entering a junction must be:

Accepted Answer

Equal to the total current leaving the junction

Answer

Greater than the total current leaving the junction

Answer

Less than the total current leaving the junction

Answer

Unrelated to the total current leaving the junction

Question 10

An AC circuit is characterized by:

Accepted Answer

Varying voltage and current

Answer

Constant voltage and current

Answer

Direct current and constant voltage

Answer

Direct voltage and varying current

Question 11

Which of the following materials is a good conductor of electricity?

Accepted Answer

Copper

Answer

Rubber

Answer

Wood

Answer

Plastic

Question 12

The primary function of a circuit breaker in an electrical system is to:

Accepted Answer

Interrupt the flow of current if it exceeds a safe level

Answer

Provide a path for current to flow

Answer

Store electrical energy

Answer

Convert AC to DC

Question 13

The primary purpose of a transformer in an electrical system is to:

Accepted Answer

Increase or decrease voltage

Answer

Convert AC to DC

Answer

Store electrical energy

Answer

Interrupt the flow of current

Question 14

Which of the following energy sources is considered renewable?

Accepted Answer

Solar power

Answer

Coal

Answer

Natural gas

Answer

Nuclear power

Question 15

What is the SI unit of electric current?

Accepted Answer

Ampere (A)

Answer

Watt (W)

Answer

Ohm (Ω)

Answer

Volt (V)

Question 16

According to Ohm's law, the voltage across a conductor is:

Accepted Answer

Equal to the product of current and resistance

Answer

Inversely proportional to the current through it

Answer

Not affected by the current through it

Answer

Proportional to the square of the current through it

Question 17

Which of the following is NOT a characteristic of an AC circuit?

Accepted Answer

Constant voltage

Answer

Alternating current

Answer

Varying current direction

Answer

Power factor

Question 18

Kirchhoff's current law states that:

Accepted Answer

The total current entering a junction is equal to the total current leaving the junction

Answer

The total voltage around a loop is equal to the sum of the voltages across each individual resistor

Answer

The resistance of a conductor is inversely proportional to its cross-sectional area

Answer

The power dissipated in a resistor is equal to the square of the voltage across it

Question 19

In a purely inductive circuit, the phase difference between voltage and current is:

Accepted Answer

90 degrees

Answer

0 degrees

Answer

180 degrees

Answer

270 degrees

Question 20

Which of the following is NOT a type of electrical power?

Accepted Answer

Potential power

Answer

Active power

Answer

Reactive power

Answer

Apparent power

Question 21

What is the primary purpose of a transformer?

Accepted Answer

To change the voltage level of an AC signal

Answer

To convert AC to DC

Answer

To isolate circuits from each other

Answer

To store electrical energy

Question 22

What is the main function of a fuse in an electrical circuit?

Accepted Answer

To protect the circuit from overcurrent

Answer

To regulate the voltage in the circuit

Answer

To isolate faulty components

Answer

To store electrical energy