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:

  • A. c wave
  • B. sawtooth wave
  • C. square wave
  • D. triangle wave
  • Correct Answer: Option C

A sine wave has:

  • A. four quadrants
  • B. two alternations
  • C. one period
  • D. all of the above
  • Correct Answer: Option D

A sine wave reaches maximum positive voltage at:

  • A. 90°
  • B.
  • C. –90°
  • D. 360°
  • Correct Answer: Option A

A test equipment item that has the ability to produce either square, triangular, or sawtooth waveforms is called:

  • A. a function generator
  • B. a radio frequency generator
  • C. an audio frequency generator
  • D. a frequency meter or counter
  • Correct Answer: Option A

A triangle wave consists of repeating:

  • A. positive ramps only
  • B. negative ramps only
  • C. positive and negative ramps of equal value
  • D. positive and negative ramps of unequal value
  • Correct Answer: Option C

AC effective voltage is named:

  • A. average
  • B. peak
  • C. peak-to-peak
  • D. root mean square
  • Correct Answer: Option D

How long would it take to transmit an electromagnetic wave to a receiving antenna 1,000 miles away?

  • A. 5.38 ms
  • B. 10.8 ms
  • C. 53.8 ms
  • D. 108 ms
  • Correct Answer: Option A

If a sine wave signal is 100 mV peak-to-peak, how many volts would be measured by a voltmeter?

  • A. 14.14 mV
  • B. 35.4 mV
  • C. 63.7 mV
  • D. 70.7 mV
  • Correct Answer: Option B

If a voltmeter measures a sine wave as 500 mV, what would be its average value?

  • A. 159.0 mV
  • B. 318.5 mV
  • C. 353.5 mV
  • D. 451.0 mV
  • Correct Answer: Option D

If a waveform period is determined to be 10 microseconds in duration, what is the frequency of the signal?

  • A. 100 Hz
  • B. 1000 Hz
  • C. 10 kHz
  • D. 100 kHz
  • Correct Answer: Option D

If current varies periodically from zero to a maximum, back to zero, and then repeats, the signal is:

  • A. direct
  • B. alternating
  • C. pulsating
  • D. repetitive
  • Correct Answer: Option C

If the frequency of a radio wave is increased, then its wavelength will:

  • A. increase
  • B. decrease
  • C. remain the same
  • D. cannot tell
  • Correct Answer: Option B

One adjustable knob on the oscilloscope that allows the trace to be aligned with a reference graticule is called the:

  • A. position control
  • B. focus control
  • C. intensity control
  • D. volts/cm control
  • 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:

  • A. time/cm control
  • B. position control
  • C. intensity control
  • D. volts/cm control
  • 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:

  • A. focus control
  • B. time/cm control
  • C. intensity control
  • D. volts/cm control
  • Correct Answer: Option B

Power companies supply ac, not dc, because:

  • A. it is easier to transmit ac
  • B. there is no longer a need for dc
  • C. dc is more dangerous
  • D. there are not enough batteries
  • Correct Answer: Option A

Signal comparisons may be most easily seen when using which item of test equipment?

  • A. spectrum analyzer
  • B. multimeter
  • C. function generator
  • D. dual trace oscilloscope
  • Correct Answer: Option D

Test equipment selection enables the technician to both generate signals and:

  • A. change circuit conditions
  • B. inject signals
  • C. sense circuit conditions
  • D. change signal frequencies
  • 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.

  • A. pulse width
  • B. duty cycle
  • C. phase shift
  • D. active ratio
  • 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:

  • A. amplitude
  • B. frequency
  • C. wavelength
  • D. period
  • Correct Answer: Option C

The letter in the Greek alphabet used to represent wavelength is __________.

  • A. lambda
  • B. theta
  • C. omega
  • D. delta
  • Correct Answer: Option A

The magnitude that an alternation varies from zero is called its:

  • A. altitude
  • B. amplitude
  • C. attitude
  • D. polarity
  • Correct Answer: Option B

The phase difference between sine waves of different frequencies is:

  • A. equal to their frequency differences
  • B. the difference in their fixed time displacement
  • C. the same throughout time
  • D. constantly changing
  • Correct Answer: Option B

The power that is distributed from a power plant to your home is:

  • A. high voltage to high voltage
  • B. low voltage to high voltage
  • C. high voltage to low voltage
  • D. low voltage to low voltage
  • Correct Answer: Option C

What are the two main applications for ac?

  • A. direct, pulsating
  • B. electric, magnetic
  • C. power, information
  • D. static, dynamic
  • Correct Answer: Option C

What does the CRT oscilloscope display?

  • A. voltage and period
  • B. current and frequency
  • C. rms voltage and current
  • D. frequency and voltage
  • Correct Answer: Option A

What is the average value of a 12 V peak wave?

  • A. 3.82 V
  • B. 4.24 V
  • C. 7.64 V
  • D. 9.42 V
  • Correct Answer: Option C

What is the name of a device that converts sound waves to electrical waves?

  • A. an amplifier
  • B. an antenna
  • C. a filter
  • D. a microphone
  • Correct Answer: Option D

What is the name of a device used to directly measure the frequency of a periodic wave?

  • A. oscilloscope
  • B. frequency meter or counter
  • C. audio frequency generator
  • D. radio frequency generator
  • Correct Answer: Option B

What is the peak value of a household appliance that uses a 230 V ac source?

  • A. 163 V
  • B. 230 V
  • C. 325 V
  • D. 480 V
  • Correct Answer: Option C

What is the peak-to peak voltage of a 56 Vrms ac voltage?

  • A. 158 V
  • B. 164 V
  • C. 82 V
  • D. 79 V
  • Correct Answer: Option A

What is the peak-to-peak current value when an ammeter measures a 20 mA value?

  • A. 14 mA
  • B. 28 mA
  • C. 40 mA
  • D. 57 mA
  • Correct Answer: Option D

What is the period of a 16 MHz sine wave?

  • A. 196 ns
  • B. 62.5 ns
  • C. 31.25 ns
  • D. 19.9 ns
  • 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?

  • A. 3 ms
  • B. 16 ms
  • C. 4 ms
  • D. 20 ms
  • 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)

  • A. 50 ms
  • B. 100 ms
  • C. 150 ms
  • D. 200 ms
  • Correct Answer: Option C

What term expresses the frequency of a rectangular wave?

  • A. Hz
  • B. period
  • C. PRF
  • D. PRT
  • Correct Answer: Option C

What voltage will an ac voltmeter display?

  • A. rms
  • B. average
  • C. peak
  • D. peak-to-peak
  • Correct Answer: Option A

Which control should be moved to display more cycles of a signal on an oscilloscope?

  • A. horizontal position to left or right
  • B. volts/cm to a smaller number
  • C. vertical position to top or bottom
  • D. time/cm to a higher setting
  • Correct Answer: Option D

Which percentages of full-amplitude rise time are used for a pulse wave?

  • A. 0 to 50 percent
  • B. 0 to 100 percent
  • C. 5 to 95 percent
  • D. 10 to 90 percent
  • Correct Answer: Option D

Why is ac current transfer more effective than dc current transfer over long distances?

  • A. due to the height of power lines
  • B. due to the use of ac generators
  • C. due to step-up and step-down transformers reducing I2R losses
  • D. due to very high voltages
  • Correct Answer: Option C