Top 100 Basic Electrical Engineering MCQ

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Top 100 Basic Electrical Engineering MCQ for competitive exams, quizzes, and tests.

Electric current is measured by which instrument

Electric current is measured by which instrument:

  1. Voltmeter
  2. Ammeter
  3. Ohmmeter
  4. Wattmeter

Correct answer: 2. Ammeter

The SI unit of electric current is ampere’s which is measured by using ammeter

No current flows through two bodies if they have same

No current flows through two bodies if they have same ________:

  1. Potential
  2. Charge
  3. Capacity
  4. Temperature

Correct answer: 1. Potential

Effect of tripling current on the power of constant resistance circuit

In the certain circuit, having constant resistance the current is tripled, what will happen to power:

  1. It will remain the same
  2. It will increase by 9 times
  3. It will decrease by 9 times
  4. It will increase by three times

Answer: 2. It will increase by 9 times

Illustration: Power (P) = I2R

By increasing current by three times I = 3I new power P(N) becomes

P(N) = (3I)2R = 9 I2R = p (I2R) = 9 (P)

Power increases by three times

Role of EMF in Electric Circuits

Role of EMF in electric circuits is to:

  1. Increase resistance of circuit
  2. Decrease resistance of circuit
  3. Provide potential difference
  4. All of these

Correct answer: 3. Provide potential difference

Semiconductors have which type of temperature coefficient of resistance

Semiconductors have ____________ temperature coefficient of resistance:

  1. Negative
  2. Positive
  3. Zero
  4. None of these

Correct answer: 1. Negative

In semiconductors, an increase in the temperature of material results in an increase in charge-carrier concentration. This, in turn, results in availability of a higher number of charge carriers thus increasing the conductivity of the semiconductors. which decreases the resistivity of the semiconductor material with the rise in temperature.

What is the reciprocal of conductivity

What is the reciprocal of conductivity:

  1. Current
  2. Inductivity
  3. Resistivity
  4. Resistance

Correct answer: 3. Resisivity

Resistance at any diameter of wire forming circle

Certain wire has a resistance of 10 Ω. It is bent to form a circle. What resistance will an ohmmeter connected on any diameter of the circle will measure ideally:

  1. 0.9 Ω
  2. 3.33 Ω
  3. 1.5 Ω
  4. 2.5 Ω
  5. 5 Ω

Correct answer 4. 2.5 Ω

Illustration:

5 ohm || 5 ohm = 2.5 ohms (MCQs on Series and Parallel resistors)

Effect of adding new series resistors on Power dissipation of previous resistor

A resistor having resistance ‘R’ dissipates power ‘P’ when connected to a voltage source E. If another resistor ‘R1’ is connected in series to ‘R’, then the power ‘P’ dissipated by ‘R’ will:

  1. Increase
  2. Decrease
  3. Remains the same as it was before

Correct answer: 1. Decrease

What happens when cells are arranged in parallel

Which of the following statement is correct about parallel connection of cells:

  1. The EMF increases
  2. The EMF decreases
  3. The current capacity increases
  4. The current capacity decreases

Correct answer: 3. The current capacity increases

Similar MCQ: Electric current is measured in

Two lamps having rated powers of 100 W@230 V and 50 W @230 V respectively. If R1 = 100 W lamp and R2 = 50 W lamp, then the ratio of their resistances is

Two lamps having rated powers of 100 W@230 V and 50 W @230 V respectively. If R1 is the resistance of 100 W lamp and R2 is resistance of 50 W lamp, then the ratio of their resistances is:

  1. R1 = R2
  2. R1 = 2R2
  3. R1 = 1 + R2
  4. R1 = R2/2

Correct answer: 4. R1 = R2/2

Explanation: Since both resistors are rated for same voltage, then

R1 * P1 = R2 * P2

R1 * 100 = R2 * 50

R1 = R2 * 50 / 100

R1 = R2/2

The nameplate of a water heater mentions 2645 W, 230 V. The resistance of element is

The nameplate of a water heater mentions 2645 W, 230 V. The resistance of element is:

  1. 1.15 ohms
  2. 11.5 ohms
  3. 20 ohms
  4. 608 kohms

Correct answer: 3. 20 ohms

Explanation: R = V2/P

R = (230)2/2645 = 20 ohms

Electric current is scalar or vector

Electric current is:

  1. Scalar quantity
  2. Vector quantity

Correct answer: 1. Scalar quantity

Electric current is defined as the amount of charge passing through a surface per unit time.

I = Q/t

Since both components in formula (charge and the time) are scalar quantities the current is a scalar quantity.

Good to know: While current is a scalar quantity, the current density is not. Current density is actually a vectorial quantity

Which one of the following is an an example of non-ohmic resistance

Which one of the following is an an example of non-ohmic resistance:

  1. Aluminum
  2. Tungsten
  3. Silver
  4. Carbon

Correct answer: 4. Carbon

Carbon resistance is an example of non-ohmic resistance.

The temperature coefficient of resistance depends on on which factor

The temperature coefficient of resistance depends on on which factor:

  1. Length of material
  2. Nature of material and temperature
  3. Cross sectional area of material
  4. Volume of material

Correct answer: 2. Nature of material and temperature

Ampere – second is a unit of which electrical quantity

Ampere – second is a unit of which electrical quantity:

  1. E.M.F
  2. Magnetostatic force per meter2
  3. Charge
  4. Capacitance

Correct answer: 3. Charge

Ampere – second or coulomb is unit of Electric charge

Current division principle is applicable for

Current division principle is applicable for:

  1. Series circuits only
  2. Parallel circuits only
  3. Both of these
  4. None of these

Correct answer: 2. Parallel circuits only

See also: Top 10 MCQ on Current Divider Rule

Correct statement of VDR Principle

Which of the equations given below correctly express the voltage divider principle:

  1. Vx = {(Rx + Req)/ Req} * Vs
  2. Vx = (Rx / Req) * Vx
  3. Vx = (Req / Rx) * Vs
  4. Vx = (Rx / Req) * Vs

Correct answer: 4. Vx = (Rx / Req) * Vs

Basic Resistance formula

The resistance R of a material having length l and area of cross section A is mathematically expressed as:

  1. R = ρlA
  2. R = ρl + A
  3. R = ρl/A
  4. R = ρl (1+ σς/A)

Correct answer: 3. R = ρl/A

Electrical devices and appliances are not connected in series because

Electrical devices and appliances are not connected in series because:

  1. More power losses occur in series
  2. Series circuit is complex to design
  3. Devices have different current rating
  4. All of these

Correct answer: 3. Devices have different current rating

How long does it take for a 75-watt soldering iron to dissipate the energy of 7500 J

How long does it take for a 75-watt soldering iron to dissipate the energy of 7500 J:

  1. 50 seconds
  2. 100 seconds
  3. 1250 seconds
  4. 562500 seconds
  5. None of these

Correct answer: 2. 100 seconds

The resistance of a linear circuit

The resistance of a linear circuit:

  1. Changes with a change in voltage
  2. Changes with a change in current
  3. Doesn’t changes with change in voltage and current
  4. 1 and 2

Correct answer: 3. Doesn’t changes with change in voltage and current

To find the value of voltage sources connected to 6 ohms resistor

A 6-ohm resistor connects in series to an unknown voltage source. An ammeter when connected in series measures a current flow of 2 Amps. What is the value of the voltage source?

  1. 2 V
  2. 3 V
  3. 6 V
  4. 12 V

Correct answer: 4. 12 V

From Ohm’s law formula: V = IR = 2 A * 6 ohms = 12 V

Four cells of 2 Ω are connected in parallel. The overall resistance of the battery is:

Four cells of 2 Ω are connected in parallel. The overall resistance of the battery is:

  1. 0.25 Ω
  2. 0.5 Ω
  3. 1 Ω
  4. 2 Ω

Correct answer: 2. 0.5 Ω

For same resistors in parallel: R/n = 2 ohm/4 = 0.5 Ω

What is the Temperature coefficient of insulators

Generally, the temperature coefficient of insulators is:

  1. Positive
  2. Negative
  3. Zero
  4. None of these

Correct answer: 2. Negative

When the resistance of materials falls with an increase in temperature, the material is said to posses a negtaive temperature coefficient. Generally insulators have a negative temperature coefficient.

The specific resistance of a wire depends on

The specific resistance of a wire depends on:

  1. Its dimension
  2. Its length
  3. Its material
  4. Its cross sectional area
  5. All of these

Correct answer: 3. Its material

The specific resistance of a conductor is the resistance of a conductor that has unit length and a unit area of cross-section. Note that specific resistance is a property of the material and it depends on the material.

When resistors are connected in parallel which of following is correct about current

When resistors are connected in parallel which of following is correct about current:

  1. It divides in the direct ratio of resistance
  2. It divides in the inverse ratio of resistance
  3. None of the above

Correct answer: 2. It divides in the inverse ratio of resistance

The superposition theorem is applied when the circuit contains

The superposition theorem is applied when the circuit contains:

  1. All passive elements
  2. All active elements
  3. A single voltage or current source
  4. Multiple sources

Correct answer: 4. Multiple sources

The superposition theorem is applied when circuit contains two or more than two sources.

Statement of Superposition theorem:

The total current through or voltage across a resistor or branch can be determined by summing the effects due to each independent source.

3 thoughts on “Top 100 Basic Electrical Engineering MCQ”

  1. These questions are very importat for electrical engineering students therefore awill appretiate U to continue posting just like these questions

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