Key Topic 12: Waveforms

Question 1

3-12B1: At pi/3 radians, what is the amplitude of a sine-wave having a peak value of 5 volts?

A. -4.3 volts.
B. -2.5 volts.
C. +2.5 volts.
D. +4.3 volts.

Answer 1

D. +4.3 volts.

Question 2

3-12B2: At 150 degrees, what is the amplitude of a sine-wave having a peak value of 5 volts?

A. -4.3 volts.
B. -2.5 volts.
C. +2.5 volts.
D. +4.3 volts.

Answer 2

C. +2.5 volts.

Question 3

3-12B3: At 240 degrees, what is the amplitude of a sine-wave having a peak value of 5 volts?

A. -4.3 volts.
B. -2.5 volts.
C. +2.5 volts.
D. +4.3 volts.

Answer 3

A. -4.3 volts.

Question 4

3-12B4: What is the equivalent to the root-mean-square value of an AC voltage?

A. AC voltage is the square root of the average AC value.
B. The DC voltage causing the same heating in a given resistor at the peak AC voltage.
C. The AC voltage found by taking the square of the average value of the peak AC voltage.
D. The DC voltage causing the same heating in a given resistor as the RMS AC voltage of the same value.

Answer 4

D. The DC voltage causing the same heating in a given resistor as the RMS AC voltage of the same value.

Question 5

3-12B5: What is the RMS value of a 340-volt peak-to-peak pure sine wave?

A. 170 volts AC.
B. 240 volts AC.
C. 120 volts AC.
D. 350 volts AC.

Answer 5

C. 120 volts AC.

Question 6

3-12B6: Determine the phase relationship between the two signals shown in Figure 3B3.

A. A is lagging B by 90 degrees.
B. B is lagging A by 90 degrees.
C. A is leading B by 90 degrees.
D. B is leading A by 90 degrees.

Answer 6

B. B is lagging A by 90 degrees.