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• 1. AC Theory Modules
• 2. Capacitors
• 3. Inductors
• 4. DC Transients
• 5. Phase and Phasors
• 6. Reactance
• 7. Impedance
• 8. Filters & Wave shaping
• 9. LCR Series Circuits
• 10. LCR Parallel Circuits
• 11. Transformers

Module 5.5

Phasor Quiz

Try this quiz, based on the information you can find in Module 5. Hopefully it won´t be too difficult. Submit your answers to see how well you did. If you got any answers wrong, you´ll be told where to find the right answer, so you can learn more about AC circuits and Phasors before you have another try.

1.

In an inductor, an increase in the value of the internal resistance has the effect of: (Complete the sentence).

• a) Increasing the inductance.
• b) Decreasing the phase difference between the inductor voltage (V_L and current (I_L).
• c) Decreasing the inductance.
• d) Increasing the phase difference between the inductor voltage (V_L and current (I_L).

2.

In a capacitor: (Complete the sentence).

• a) Current leads voltage by 90°.
• b) Voltage leads current by 90°.
• c) Current Lags Voltage by between 0° and 90°.
• d) Voltage leads current by between 0° and 90°.

3.

Which property of a sine wave does the length of a phasor represent?

• a) Frequency.
• b) Phase.
• c) Amplitude.
• d) Instantaneous value.

4.

Refer to Fig. 5.5.1: Which of the following statements about Fig 5.5.1 is true?

• a) All the waves depicted have the same frequency and same amplitude.
• b) All the waves depicted have the same phase and same frequency.
• c) All the waves depicted have the same shape and same frequency.
• d) All the waves depicted have the same phase and same shape.

5.

Refer to Fig 5.5.2: What is the phase difference θ between the supply voltage and the supply current?

• a) 53°
• b) 37°
• c) 30°
• d) 59°

6.

Refer to Fig 5.5.3: Which of the phasor diagrams describes a CR series Circuit?

• a) Diagram a.
• b) Diagram b.
• c) Diagram c.
• d) Diagram d.

7.

For the phasor diagram shown in Fig 5.5.4, calculate the phase angle θ between I_S and V_S.

• a) 31°
• b) 53°
• c) 41°
• d) 37°

8.

In a parallel LCR circuit, which of the following properties is used as the reference phasor?

• a) Supply current (I_S ).
• b) Reactive voltage (V_C − V_L) .
• c) Supply voltage (V_S) .
• d) Reactive voltage (V_L − V_C) .

9.

A phasor representing a 1kHz sine wave will rotate through how many complete radians in one second?

• a) 360,000
• b) 6283
• c) 1000
• d) 3142

10.

In a phasor diagram, the frequency of each of the waves shown by the phasors is:

• a) The same for all waves, and shown by the point of origin of the phasors.
• b) Different for each wave ,and proportional to the different lengths of the phasors.
• c) Different for each wave, and shown by the change in angle of the phasors.
• d) Not shown.

© 2007− 2024 Eric Coates MA BSc. (Hons) All rights reserved. (Revision 15.00 29th December 2020)