Alternating Current Vs Direct Current MCQs
Practice and Learn through MCQs and Quizzes. W3Definitions.com have 40 Alternating Current Vs Direct Current MCQs
A rectangular wave that has a duty cycle of 50 percent could be called a:
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A. c wave
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B. sawtooth wave
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C. square wave
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D. triangle wave
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Correct Answer: Option C
A sine wave has:
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A. four quadrants
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B. two alternations
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C. one period
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D. all of the above
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Correct Answer: Option D
A sine wave reaches maximum positive voltage at:
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A. 90°
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B. 0°
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C. –90°
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D. 360°
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Correct Answer: Option A
A test equipment item that has the ability to produce either square, triangular, or sawtooth waveforms is called:
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A. a function generator
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B. a radio frequency generator
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C. an audio frequency generator
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D. a frequency meter or counter
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Correct Answer: Option A
A triangle wave consists of repeating:
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A. positive ramps only
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B. negative ramps only
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C. positive and negative ramps of equal value
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D. positive and negative ramps of unequal value
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Correct Answer: Option C
AC effective voltage is named:
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A. average
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B. peak
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C. peak-to-peak
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D. root mean square
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Correct Answer: Option D
How long would it take to transmit an electromagnetic wave to a receiving antenna 1,000 miles away?
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A. 5.38 ms
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B. 10.8 ms
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C. 53.8 ms
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D. 108 ms
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Correct Answer: Option A
If a sine wave signal is 100 mV peak-to-peak, how many volts would be measured by a voltmeter?
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A. 14.14 mV
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B. 35.4 mV
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C. 63.7 mV
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D. 70.7 mV
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Correct Answer: Option B
If a voltmeter measures a sine wave as 500 mV, what would be its average value?
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A. 159.0 mV
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B. 318.5 mV
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C. 353.5 mV
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D. 451.0 mV
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Correct Answer: Option D
If a waveform period is determined to be 10 microseconds in duration, what is the frequency of the signal?
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A. 100 Hz
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B. 1000 Hz
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C. 10 kHz
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D. 100 kHz
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Correct Answer: Option D
If current varies periodically from zero to a maximum, back to zero, and then repeats, the signal is:
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A. direct
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B. alternating
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C. pulsating
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D. repetitive
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Correct Answer: Option C
If the frequency of a radio wave is increased, then its wavelength will:
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A. increase
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B. decrease
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C. remain the same
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D. cannot tell
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Correct Answer: Option B
One adjustable knob on the oscilloscope that allows the trace to be aligned with a reference graticule is called the:
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A. position control
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B. focus control
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C. intensity control
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D. volts/cm control
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Correct Answer: Option A
One oscilloscope selector knob that allows the major and minor divisions of the graticule to be used to determine a signal amplitude value is called the:
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A. time/cm control
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B. position control
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C. intensity control
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D. volts/cm control
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Correct Answer: Option D
One oscilloscope selector knob that allows the major and minor divisions of the graticule to be used to determine a waveform period is called a:
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A. focus control
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B. time/cm control
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C. intensity control
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D. volts/cm control
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Correct Answer: Option B
Power companies supply ac, not dc, because:
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A. it is easier to transmit ac
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B. there is no longer a need for dc
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C. dc is more dangerous
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D. there are not enough batteries
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Correct Answer: Option A
Signal comparisons may be most easily seen when using which item of test equipment?
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A. spectrum analyzer
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B. multimeter
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C. function generator
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D. dual trace oscilloscope
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Correct Answer: Option D
Test equipment selection enables the technician to both generate signals and:
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A. change circuit conditions
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B. inject signals
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C. sense circuit conditions
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D. change signal frequencies
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Correct Answer: Option C
The __________ is defined as the ratio of a pulse width (positive or negative pulse or cycle) to the overall period of time of the wave.
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A. pulse width
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B. duty cycle
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C. phase shift
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D. active ratio
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Correct Answer: Option B
The distance that a signal’s energy can travel in the time it takes for one cycle to occur is called the signal’s:
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A. amplitude
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B. frequency
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C. wavelength
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D. period
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Correct Answer: Option C
The letter in the Greek alphabet used to represent wavelength is __________.
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A. lambda
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B. theta
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C. omega
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D. delta
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Correct Answer: Option A
The magnitude that an alternation varies from zero is called its:
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A. altitude
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B. amplitude
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C. attitude
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D. polarity
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Correct Answer: Option B
The phase difference between sine waves of different frequencies is:
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A. equal to their frequency differences
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B. the difference in their fixed time displacement
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C. the same throughout time
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D. constantly changing
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Correct Answer: Option B
The power that is distributed from a power plant to your home is:
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A. high voltage to high voltage
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B. low voltage to high voltage
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C. high voltage to low voltage
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D. low voltage to low voltage
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Correct Answer: Option C
What are the two main applications for ac?
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A. direct, pulsating
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B. electric, magnetic
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C. power, information
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D. static, dynamic
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Correct Answer: Option C
What does the CRT oscilloscope display?
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A. voltage and period
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B. current and frequency
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C. rms voltage and current
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D. frequency and voltage
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Correct Answer: Option A
What is the average value of a 12 V peak wave?
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A. 3.82 V
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B. 4.24 V
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C. 7.64 V
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D. 9.42 V
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Correct Answer: Option C
What is the name of a device that converts sound waves to electrical waves?
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A. an amplifier
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B. an antenna
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C. a filter
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D. a microphone
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Correct Answer: Option D
What is the name of a device used to directly measure the frequency of a periodic wave?
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A. oscilloscope
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B. frequency meter or counter
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C. audio frequency generator
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D. radio frequency generator
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Correct Answer: Option B
What is the peak value of a household appliance that uses a 230 V ac source?
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A. 163 V
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B. 230 V
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C. 325 V
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D. 480 V
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Correct Answer: Option C
What is the peak-to peak voltage of a 56 Vrms ac voltage?
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A. 158 V
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B. 164 V
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C. 82 V
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D. 79 V
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Correct Answer: Option A
What is the peak-to-peak current value when an ammeter measures a 20 mA value?
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A. 14 mA
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B. 28 mA
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C. 40 mA
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D. 57 mA
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Correct Answer: Option D
What is the period of a 16 MHz sine wave?
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A. 196 ns
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B. 62.5 ns
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C. 31.25 ns
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D. 19.9 ns
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Correct Answer: Option B
What is the waveform period difference between the 60 Hz electricity used in this country and the 50 Hz used in Europe?
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A. 3 ms
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B. 16 ms
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C. 4 ms
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D. 20 ms
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Correct Answer: Option A
What is the waveform period of a square wave signal that horizontally covers 3 major divisions per cycle? (time/cm = 50 ms)
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A. 50 ms
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B. 100 ms
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C. 150 ms
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D. 200 ms
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Correct Answer: Option C
What term expresses the frequency of a rectangular wave?
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A. Hz
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B. period
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C. PRF
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D. PRT
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Correct Answer: Option C
What voltage will an ac voltmeter display?
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A. rms
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B. average
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C. peak
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D. peak-to-peak
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Correct Answer: Option A
Which control should be moved to display more cycles of a signal on an oscilloscope?
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A. horizontal position to left or right
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B. volts/cm to a smaller number
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C. vertical position to top or bottom
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D. time/cm to a higher setting
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Correct Answer: Option D
Which percentages of full-amplitude rise time are used for a pulse wave?
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A. 0 to 50 percent
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B. 0 to 100 percent
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C. 5 to 95 percent
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D. 10 to 90 percent
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Correct Answer: Option D
Why is ac current transfer more effective than dc current transfer over long distances?
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A. due to the height of power lines
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B. due to the use of ac generators
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C. due to step-up and step-down transformers reducing I2R losses
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D. due to very high voltages
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Correct Answer: Option C