Electrical Engineering Questions and Answers


101)

A phasor represents

Answer: Option A

Explanation:

The phasor diagram represents both the magnitude and phase angle.
102)

Sine wave A has a positive-going zero crossing at 45°. Sine wave B has a positive-going zero crossing at 60°. Which of the following statements is true?

Answer: Option A

Explanation:

Option A is the correct option. Because if you plot the graph as angles on x-axis a and respective variable(voltage or current) on y-axis, you will observe that wave A is 15 degrees before that of wave B. Therefore you can say wave A leading wave B by 15 degrees.
103)

If a sine wave goes through 10 cycles in 20 μs, the period is

Answer: Option C

Explanation:

Period = Time/Cycle

= 20/ 10
= 2
104)

Two series resistors are connected to an ac source. If there are 7.5 V rms across one resistor and 4.2 V rms across the other, the peak source voltage is

Answer: Option A

Explanation:

peak source voltage= (v1rms+v2rms)*1.414
= (7.5+4.2)*1.414 = 16.54
105)

When a sine wave has a frequency of 100 Hz in 12 s it goes through

Answer: Option D

Explanation:

Frequency = Number of cycles / Unit time
No of cycles = Frequency * Unit time
Frequency =100Hz Time=12s
No of cycles = 100*12= 1200 cycles

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