Resistors play a crucial role in the functioning of various circuits. The resistor is a passive component that opposes the flow of electric current in circuits. It is designed to regulate the current that can pass through a circuit, which controls the amount of voltage and power delivered to a device or system. Resistors come in different shapes, sizes, and types, each with unique properties and characteristics. Some of the most common resistors include carbon film resistors, metal film resistors, wire-wound resistors, and many more. The type of resistor used in a circuit depends on the particular application and requirements of the circuit. One of the most critical aspects of resistors is their resistance value, measured in ohms. The resistance value determines how much current can pass through the resistor and how much voltage will be dropped across it. Resistors with a higher resistance value will allow less current to pass through, while resistors with a lower resistance value will allow more current to pass through. Another essential property of resistors is their tolerance, which is the degree of accuracy with which the resistance value is measured. Resistors with a high tolerance value may have a broader range of resistance values than those with a low tolerance value. Overall, resistors are an essential component in electronic circuits and play a critical role in controlling the flow of current and voltage. Understanding the different types of resistors and their properties is crucial for any electronics enthusiast or professional to design and build circuits that function correctly and efficiently.

In this post Electrical Engineering Online shares Objective Electrical MCQ Questions on Resistors.

## What is the primary function of a resistor in an electrical circuit

What is the primary function of a resistor in an electrical circuit?

- To store electrical energy
- To convert electrical energy into mechanical energy
- To regulate voltage
- To limit the flow of current

Correct Answer: 4. To limit the flow of current

**Explanation:** The primary function of a resistor is to restrict or limit the flow of electric current in a circuit.

## What is the SI unit of resistance

What is the SI unit of resistance?

- Volt
- Ampere
- Ohm
- Watt

Correct Answer: 3. Ohm

**Explanation:** The SI unit of resistance is the Ohm (Ω).

## Which of the following materials is commonly used for manufacturing resistors

Which of the following materials is commonly used for manufacturing resistors?

- Copper
- Aluminum
- Carbon
- Silver

Correct Answer: 3. Carbon

**Explanation:** Carbon is a commonly used material for manufacturing resistors due to its high resistivity and stability.

## What happens to the resistance of a wire if its length is doubled, assuming other factors remain constant

What happens to the resistance of a wire if its length is doubled, assuming other factors remain constant?

- The resistance doubles
- The resistance halves
- The resistance remains the same
- The resistance becomes zero

Correct Answer: 1. The resistance doubles

**Explanation:** The resistance of a wire is directly proportional to its length. Doubling the length of the wire will result in double the resistance.

## Which of the following factors does NOT affect the resistance of a wire

Which of the following factors does NOT affect the resistance of a wire?

- Length of the wire
- Cross-sectional area of the wire
- Temperature of the wire
- Material of the wire

Correct Answer: 3. Temperature of the wire

**Explanation:** Temperature does affect the resistance of a wire. As the temperature increases, the resistance typically increases for most materials.

## What happens to the resistance of a wire if its cross-sectional area is doubled, assuming other factors remain constant

What happens to the resistance of a wire if its cross-sectional area is doubled, assuming other factors remain constant?

- The resistance doubles
- The resistance halves
- The resistance remains the same
- The resistance becomes zero

Correct Answer: 2. The resistance halves

**Explanation:** The resistance of a wire is inversely proportional to its cross-sectional area. Doubling the cross-sectional area of the wire will result in halving the resistance.

## Which of the following types of resistors has a fixed resistance value

Which of the following types of resistors has a fixed resistance value?

- Variable resistor
- Thermistor
- Light-dependent resistor (LDR)
- Carbon resistor

Correct Answer: 4. Carbon resistor

**Explanation:** A fixed resistor has a predetermined resistance value that does not change. It is commonly used in circuits where a specific resistance is required.

## What is the color code for a resistor with the color bands: Brown, Black, Red, and Gold

What is the color code for a resistor with the color bands: Brown, Black, Red, and Gold

- 100 ohms, 1% tolerance
- 10 kilohms, 2% tolerance
- 1 megaohm, 5% tolerance
- 100 megaohms, 10% tolerance

Correct Answer: 3. 1 megaohm, 5% tolerance

**Explanation:** The color code for resistors is a standard system to indicate their resistance value and tolerance. In this case, the resistor has a resistance of 1 megaohm (1MΩ) with a tolerance of 5%.

## Which of the following statements is true about resistors in series

Which of the following statements is true about resistors in series?

- The total resistance is equal to the sum of individual resistances
- The total resistance is always lower than the smallest individual resistance
- The total resistance is always higher than the largest individual resistance
- The total resistance depends on the voltage across each resistor

Correct Answer: 1. The total resistance is equal to the sum of individual resistances.

**Explanation:** In a series circuit, the total resistance equals the sum of the individual resistances. This can be calculated using the formula: Rt = R1 + R2 + R3 + … Rn

## Which of the following statements is true about resistors in parallel

Which of the following statements is true about resistors in parallel?

- The total resistance is equal to the sum of individual resistances
- The total resistance is always lower than the smallest individual resistance
- The total resistance is always higher than the largest individual resistance
- The total resistance depends on the voltage across each resistor

Correct Answer: 2. The total resistance is always lower than the smallest individual resistance.

**Explanation:** In a parallel circuit, the total resistance is always lesser compared to the smallest individual resistance. This can be calculated using the formula: 1/Rt = 1/R1 + 1/R2 + 1/R3 + … + 1/Rn

## What is the power rating of a resistor

What is the power rating of a resistor?

- The maximum voltage it can handle
- The maximum current it can handle
- The maximum heat it can dissipate without damage
- The maximum resistance it can handle

Correct Answer: 3. The maximum heat it can dissipate without damage

Explanation: The power rating of a resistor indicates the maximum amount of heat the resistor can dissipate without being damaged. It is usually specified in watts.

## When resistors are connected in series configuration, the total resistance is

When resistors are connected in series configuration, the total resistance is:

- The sum of their individual resistances
- The average of their individual resistances
- The product of their individual resistances
- The reciprocal of their individual resistances

Correct Answer: 1. The sum of their individual resistances.

**Explanation:** When resistors are connected in series configuration, the total resistance is simply the sum of their individual resistance values.

## When resistors are connected in parallel configuration, the total resistance is

When resistors are connected in parallel configuration , the total resistance is:

- The sum of their individual resistances
- The average of their individual resistances
- The product of their individual resistances
- The reciprocal of their individual resistances

Correct Answer: 4. The reciprocal of their individual resistances

**Explanation:** When resistors are connected in parallel configuration, the reciprocal of the total resistance is equal to the sum of the reciprocals of their individual resistances.

## What happens to the total resistance when resistors are connected in series

What happens to the total resistance when resistors are connected in series

- The total resistance decreases
- The total resistance increases
- The total resistance remains the same
- It depends on the specific values of the resistors

Correct Answer: 2. The total resistance increases.

**Explanation:** When resistors are connected in series, the total resistance increases as the individual resistances increase.

## What happens to the total resistance when resistors are connected in parallel

What happens to the total resistance when resistors are connected in parallel?

- The total resistance decreases
- The total resistance increases
- The total resistance remains the same
- It depends on the specific values of the resistors

Correct Answer: 1. The total resistance decreases.

**Explanation:** When resistors are connected in parallel, the total resistance decreases as the reciprocal of the total resistance is the sum of the reciprocals of the individual resistances.

## Which type of resistor is specifically designed to change its resistance value

Which type of resistor is specifically designed to change its resistance value?

- Fixed resistor
- Potentiometer
- Precision resistor
- Carbon composition resistor

**Explanation:** A variable resistor, potentiometer, or rheostat is specifically designed to change its resistance value. It allows for adjusting the resistance within a specified range to control the current or voltage in a circuit.

## Which of the following statements is true about the resistance-temperature relationship of most conductive materials

Which of the following statements is true about the resistance-temperature relationship of most conductive materials?

- The resistance decreases with an increase in temperature
- The resistance remains constant with temperature changes
- The resistance increases with an increase in temperature
- The resistance varies randomly with temperature

Correct Answer: 3. The resistance increases with an increase in temperature.

**Explanation:** Most conductive materials exhibit a positive temperature coefficient of resistance, meaning that their resistance increases as the temperature increases.

## What is the purpose of using a resistor in an LED circuit

What is the purpose of using a resistor in an LED circuit?

- To regulate the LED’s brightness
- To protect the LED from excessive current
- To decrease the LED’s resistance
- To increase the LED’s forward voltage

Correct Answer: 2. To protect the LED from excessive current

Explanation: LEDs are current-sensitive devices, and a resistor is used in series with an LED to limit the current flowing through it. This protects the LED from excessive current, which could damage or destroy it.

## What is the tolerance of a resistor

What is the tolerance of a resistor?

- Its ability to handle high voltages
- Its ability to handle high temperatures
- The range within which its resistance value can deviate
- The range within which its power dissipation can vary

Correct Answer: 3. The range within which its resistance value can deviate

Explanation: The tolerance of a resistor is a measure of the allowed deviation in its resistance value from the specified or nominal value. It indicates the range within which the actual resistance of the resistor can vary.

## Which of the following resistor color bands represents the multiplier value

Which of the following resistor color bands represents the multiplier value?

- First band
- Second band
- Third band
- Fourth band

Correct Answer: 3. Third band

**Explanation:** The third band represents the multiplier value in a four-band resistor color code system. It indicates the number of zeros to be added after the first two significant digits to determine the resistance value.