Phasor Representation of Alternating Quantities MCQ [Free PDF] – Objective Question Answer for Phasor Representation of Alternating Quantities Quiz

1. For addition and subtraction of phasors, we use the _________ form.

A. Rectangular
B. Polar
C. Either rectangular or polar
D. Neither rectangular nor polar

Answer: A

For addition and subtraction of phasors, we use the rectangular form because in the rectangular form we can only add the real part and the complex part separately to get the total value.

 

2. For multiplication and division of phasors, we use ____________ form.

A. Rectangular
B. Polar
C. Either rectangular or polar
D. Neither rectangular nor polar

Answer: B

For multiplication and division of phasors, we use the polar form because in the polar form we just multiply or divide the values and add or subtract the angles.

 

3. If a voltage of 2+5j and another voltage of 3+ 6j flow through two different resistors, connected in series, in a circuit, find the total voltage in the circuit.

A. 2+5j V
B. 3+6j V
C. 5+11j V
D. 5+10j V

Answer: C

The total voltage in the circuit is the sum of the two voltages where we add the real parts and imaginary parts separately.

Therefore, Vtotal = 5+11j V.

 

4. Find the total current in the circuit if two currents of 4+5j flow in the circuit.

A. 4+5j A
B. 4A
C. 5A
D. 8+10j A

Answer: D

The total current in the circuit is the sum of the two currents where we add the real parts and imaginary parts separately.

Therefore, Itotal = 8+10j A.

 

5. What is the correct expression of ω?

A. ω = 2π
B. ω = 2πf
C. ω = πf
D. ω = 2f2

Answer: B

The correct expression for ω is ω = 2πf where f is the frequency of the alternating voltage or current.

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6. Find the value of ω if the frequency is 5Hz?

A. 3.14 rad/s
B. 31.4 rad/s
C. 34 rad/s
D. 341 rad/s

Answer: B

The expression for ω is ω = 2×π×f.

Substituting the value off from the question, we get ω = 31.4 rad/s.

 

7. When one sine wave passes through the zero following the other, it is _________

A. Leading
B. Lagging
C. Neither leading nor lagging
D. Either leading or lagging

Answer: B

The sine wave is said to lag because it passes through zero following the other, hence it crosses zero after the first wave, therefore it is said to lag.

 

8. A phasor has frozen at 30 degrees, find the value of the phase angle.

A. 30 degrees
B. 60 degrees
C. 120 degrees
D. 180 degrees

Answer: A

The value of the phase angle is the value at which the phasor stops or freezes. Here, it freezes at 30 degrees, hence the phase angle is 30 degrees.

 

9. The time axis of an AC phasor represents?

A. Time
B. Phase angle
C. Voltage
D. Current

Answer: B

The time axis while measuring an AC sinusoidal voltage or current represents the phase angle when converting it to a phasor.

 

10. The length of the phasor represents?

A. Magnitude of the quantity
B. Direction of the quantity
C. Neither magnitude nor direction
D. Either magnitude or direction

Answer: A

The length of the phasor arrow represents the magnitude of the quantity, whereas the angle between the phasor and the reference represents the phase angle.

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