Electric Circuits: Master Ohm's Law, Kirchhoff's Laws, and AC Circuits

Question 1

In a series circuit, does the current flowing through each resistor have the same magnitude?

Accepted Answer

Yes

Answer

No

Answer

It depends

Question 2

Which of the following components in an electric circuit typically has the highest resistance?

Accepted Answer

Resistor

Answer

Capacitor

Answer

Inductor

Answer

Diode

Question 3

In a 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

Inversely proportional to the sum of the individual resistances

Question 4

Which of the following is a direct consequence of Kirchhoff's current law?

Accepted Answer

The algebraic sum of currents entering a node is zero.

Answer

The algebraic sum of voltages around a loop is zero.

Answer

The current through a resistor is directly proportional to the voltage across it.

Answer

The total power consumed in a circuit is equal to the product of voltage and current.

Question 5

The power factor of a circuit is a measure of the:

Accepted Answer

Ratio of real power to apparent power

Answer

Ratio of apparent power to real power

Answer

Phase angle between voltage and current

Answer

Efficiency of the circuit

Question 6

A transformer is primarily used to change the:

Accepted Answer

Voltage and current of a circuit

Answer

Frequency of a circuit

Answer

Power of a circuit

Answer

Resistance of a circuit

Question 7

The primary purpose of a fuse in an electrical circuit is to:

Accepted Answer

Protect the circuit from excessive current

Answer

Regulate the voltage in the circuit

Answer

Isolate a faulty component

Answer

Increase the power factor of the circuit

Question 8

According to Ohm's law, the current (I) flowing through a resistor is directly proportional to:

Accepted Answer

Voltage (V)

Answer

Resistance (R)

Question 9

Which of the following types of resistors exhibit variable resistance:

Accepted Answer

Variable resistor

Answer

Fixed resistor

Question 10

Kirchhoff's Current Law (KCL) states that the total current entering a junction is:

Accepted Answer

Equal to the total current leaving the junction

Answer

Greater than the total current leaving the junction

Question 11

In an AC circuit, the voltage and current sinusoids reach their maximum and minimum values at:

Accepted Answer

The same time

Answer

Different times

Question 12

The complex impedance (Z) in an AC circuit is a measure of its:

Accepted Answer

Total opposition to current flow

Answer

Resistance to current flow

Answer

Capacitance to current flow

Question 13

Capacitors in AC circuits primarily store energy in the form of an:

Accepted Answer

Electric field

Answer

Magnetic field

Answer

Electromagnetic field

Question 14

Inductors in AC circuits:

Accepted Answer

Oppose changes in current flow

Answer

Decrease the circuit's impedance

Question 15

A transformer is primarily used to:

Accepted Answer

Change the voltage and current levels in a circuit

Answer

Change the frequency of an AC signal

Question 16

The power factor (PF) of an AC circuit is a measure of the:

Accepted Answer

Ratio of real power to apparent power

Answer

Ratio of reactive power to apparent power

Question 17

Identify the fundamental differences in the operating principles of DC and AC motors.

Accepted Answer

DC motors employ fixed magnetic fields, while AC motors rely on rotating magnetic fields.

Accepted Answer

DC motors produce a constant torque, whereas AC motors generate a pulsating torque.

Answer

DC motors can operate on both AC and DC power, while AC motors require AC power exclusively.

Question 18

When working with electrical circuits, safety is crucial. Which of the following is a fundamental safety measure to reduce electrical risks?

Accepted Answer

Using insulated tools

Answer

Working directly on live circuits

Answer

Ignoring proper grounding techniques

Answer

Disregarding safety guidelines

Question 19

When working with high-voltage circuits, what is the most crucial safety measure?

Accepted Answer

Use insulated tools at all times.

Answer

Work in a secluded area to minimize distractions.

Answer

Test live wires for voltage by direct contact.

Answer

Clean electrical equipment with a damp cloth to improve conductivity.

Question 20

Which of the following is the SI unit for potential difference (voltage)?

Accepted Answer

Volt (V)

Answer

Ampere (A)

Answer

Ohm (Ω)

Answer

Coulomb (C)

Question 21

According to Ohm's law, which of the following is true for a resistor with constant voltage?

Accepted Answer

Current is directly proportional to resistance.

Answer

Resistance is proportional to voltage.

Answer

Current is inversely proportional to voltage.

Answer

Resistance is inversely proportional to current.

Question 22

In a parallel circuit, which of the following is the relationship between the total current and the branch currents?

Accepted Answer

Total current is the sum of the branch currents.

Answer

Voltage across each branch is the same.

Answer

Branch currents are equal.

Question 23

Which of the following is a fundamental Kirchhoff's law?

Accepted Answer

The sum of the currents entering a junction is equal to the sum of the currents leaving it.

Answer

Resistance of a series circuit is the sum of the branch resistances.

Answer

Voltage across a closed loop is zero.

Question 24

In a series RLC circuit, which condition results in resonance?

Accepted Answer

Inductive reactance equals capacitive reactance.

Answer

Inductance is equal to capacitance.

Answer

Voltage across the inductor is maximum.

Answer

Resistance is zero.

Question 25

Which of the following is an example of a semiconductor material?

Accepted Answer

Germanium

Answer

Copper

Answer

Aluminum

Answer

Rubber

Question 26

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

Accepted Answer

To allow current flow in only one direction

Answer

To store charge

Answer

To amplify current

Answer

To block all current flow

Question 27

State Ohm's law, the mathematical formula that relates voltage (V), current (I), and resistance (R) in an electrical circuit.

Accepted Answer

V = IR

Answer

V = I/R

Answer

I = VR

Answer

R = IV

Question 28

Calculate the current flowing through a 10-ohm resistor when connected to a 12-volt battery. Express your answer in Amperes (A).

Accepted Answer

1.2 A

Answer

12 A

Answer

2.4 A

Answer

0.83 A

Question 29

Identify the material that qualifies as a conductor of electricity.

Accepted Answer

Copper

Answer

Rubber

Answer

Wood

Answer

Plastic

Question 30

Determine the total resistance (in ohms) when two 10-ohm resistors are connected in parallel.

Accepted Answer

5 ohms

Answer

20 ohms

Answer

10 ohms

Answer

15 ohms

Question 31

State Kirchhoff's current law, which describes the behavior of current at a node in an electrical circuit.

Accepted Answer

The algebraic sum of currents entering a node is equal to the algebraic sum of currents leaving the node.

Answer

Power in a circuit is equal to the product of voltage and current.

Answer

The potential difference across a closed loop is equal to the sum of the potential differences across each component.

Question 32

In an alternating current (AC) circuit, describe the relationship between voltage and current.

Accepted Answer

Both voltage and current oscillate sinusoidally with respect to time.

Answer

Voltage and current are inversely proportional to each other.

Answer

Voltage and current remain constant over time.

Question 33

Explain the primary purpose of a transformer in an electrical circuit.

Accepted Answer

To alter voltage and current levels while maintaining power transfer.

Answer

To remove unwanted noise from the circuit.

Answer

To store electrical energy for later use.

Question 34

Identify a type of AC motor commonly used in various applications.

Accepted Answer

Induction motor

Answer

Stepper motor

Answer

DC motor

Answer

Synchronous motor

Question 35

Describe the key advantage of using alternating current (AC) over direct current (DC) in power transmission over long distances.

Accepted Answer

AC allows for efficient transmission with reduced power loss due to lower resistance.

Answer

AC is easier to generate compared to DC.

Answer

AC is inherently more efficient than DC.

Question 36

Distinguish between a series circuit and a parallel circuit based on how current and voltage behave within each type of circuit.

Accepted Answer

In a series circuit, current remains constant while voltage varies across components, whereas in a parallel circuit, voltage remains constant while current varies across branches.

Answer

In a series circuit, voltage remains constant while current varies across components, whereas in a parallel circuit, current remains constant while voltage varies across branches.

Question 37

Which of the following is a fundamental property of a resistor?

Accepted Answer

Resistance depends on the material and shape of the conductor

Answer

Resistance varies with voltage

Answer

Resistance is a measure of current flow

Answer

Resistance is constant for all materials

Question 38

In a series circuit, the equivalent resistance is:

Accepted Answer

Equal to the sum of the individual resistances

Answer

Dependent on the power supply voltage

Answer

Equal to the largest individual resistance

Answer

Equal to the smallest individual resistance

Question 39

According to Ohm's law, the current through a resistor is:

Accepted Answer

Directly proportional to the voltage and inversely proportional to the resistance

Answer

Inversely proportional to both the voltage and the resistance

Answer

Directly proportional to the resistance and inversely proportional to the voltage

Question 40

Which of the following circuit types is NOT classified as an AC circuit?

Accepted Answer

DC circuit

Answer

Parallel AC circuit

Answer

Resonant AC circuit

Answer

Series AC circuit

Question 41

The power dissipated in a resistor is:

Accepted Answer

Equal to the product of current and voltage

Answer

Independent of current and voltage

Answer

Equal to the square of the voltage

Answer

Equal to the square of the current

Question 42

In a parallel circuit, the total current is:

Accepted Answer

Equal to the sum of the individual currents

Answer

Equal to the smallest individual current

Answer

Equal to the largest individual current

Answer

Dependent on the power supply voltage

Question 43

Which of the following is a unit of electrical potential?

Accepted Answer

Volt

Answer

Ampere

Answer

Ohm

Answer

Watt

Question 44

The reciprocal of resistance is:

Accepted Answer

Conductance

Answer

Inductance

Answer

Voltage

Answer

Current

Question 45

Which of the following is used to measure electrical current?

Accepted Answer

Ammeter

Answer

Voltmeter

Answer

Ohmmeter

Answer

Wattmeter

Question 46

What is the SI unit for electric current?

Accepted Answer

Ampere

Answer

Ohm

Answer

Volt

Answer

Joule

Question 47

According to Ohm's law, the current flowing through a resistor is directly proportional to:

Accepted Answer

The voltage across the resistor

Answer

The resistance of the resistor

Answer

The square of the voltage across the resistor

Answer

The inverse of the voltage across the resistor

Question 48

Kirchhoff's current law states that the sum of currents entering a junction is:

Accepted Answer

Equal to the sum of currents leaving the junction

Answer

Less than the sum of currents leaving the junction

Answer

Greater than the sum of currents leaving the junction

Question 49

Which of the following factors influence the resistance of a wire?

Accepted Answer

Length, cross-sectional area, and material

Answer

Length and cross-sectional area only

Answer

Material and cross-sectional area only

Answer

Length and material only

Question 50

In a series circuit, the total resistance is calculated by:

Accepted Answer

Adding the individual resistances

Answer

Ignoring the individual resistances

Answer

Subtracting the individual resistances

Answer

Multiplying the individual resistances