This set of Basic Electrical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Alternating Current in a Resistive Circuit”.

1. The instantaneous voltage is a product of the resistance and the _____________ current in a resistive circuit.

a) Instantaneous

b) Average

c) RMS

d) Peak

View Answer

Explanation: The instantaneous voltage is a product of the instantaneous current and the resistance in the circuit.

2. Find the value of the instantaneous voltage if the resistance is 2 ohm and the instantaneous current in the circuit is 5A.

a) 5V

b) 2V

c) 10V

d) 2.5V

View Answer

Explanation: We know that,

v=iR, substituting the given values from the question, we get v=10V.

3. The power for a purely resistive circuit is zero when?

a) Current is zero

b) Voltage is zero

c) Both current and voltage are zero

d) Either current or voltage is zero

View Answer

Explanation: The power in a resistive circuit is the product of the voltage, current and the cosine of the phase angle. Hence if either voltage or current is zero, the power is zero.

4. If the maximum voltage in the circuit is 10V and the resistance is 5 ohm, calculate the maximum current in the circuit.

a) 1A

b) 2A

c) 3A

d) 4A

View Answer

Explanation: We know that:

Im=Vm/R

Substituting the given values from the question, we get Im=2A.

5. Calculate the resistance in the circuit if the rms voltage is 20V and the rms current is 2A.

a) 2 ohm

b) 5 ohm

c) 10 ohm

d) 20 ohm

View Answer

Explanation: We know that:

R=V/I

Substituting the given values from the question, we get R=10 ohm.

6. The correct expression for the instantaneous current in a resistive circuit is?

a) i=Vm(sint)/R

b) i=Vm(cost)/R

c) i=V(sint)/R

d) i=V(cost)/R

View Answer

Explanation: The instantaneous voltage can be written in terms of the maximum voltage in the following manner:

v=Vm(sint)

Since i=v/R, we can write, i=Vm(sint)/R.

7. Can ohm’s law be applied in an ac circuit?

a) Yes

b) No

c) Depends on the rms current

d) Depends on the rms voltage

View Answer

Explanation: Ohm’s law can be applied in ac as well as dc circuits. It can be applied in ac circuits because the condition V=IR holds true even in ac circuits.

8. What is the current found by finding the current in n equidistant regions and dividing by n?

a) RMS current

b) Average current

c) Instantaneous current

d) Total current

View Answer

Explanation: The average value of current is the sum of all the currents divided by the number of currents.

9. What is the effective value of current?

a) RMS current

b) Average current

c) Instantaneous current

d) Total current

View Answer

Explanation: Effective current is also known as the effective current. RMS stands for Root Mean Square. This value of current is obtained by squaring all the current values, finding the average and then finding the square root.

10. Find the average value of current when the current that are equidistant are 4A, 5A and 6A.

a) 5A

b) 6A

c) 15A

d) 10A

View Answer

Explanation: The average value of current is the sum of all the currents divided by the number of currents. Therefore average current= (5+4+6)/3=5A.

**Sanfoundry Global Education & Learning Series – Basic Electrical Engineering.**

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