Alternating Current vs Direct Current

Q1: 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

Q2: A sine wave reaches maximum positive voltage at:

A 90°

B

C –90°

D 360°

Q3: 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

Q4: 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

Q5: 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

Q6: 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

Q7: AC effective voltage is named:

A average

B peak

C peak-to-peak

D root mean square

Q8:
The current is flowing in what direction?

mcq6_1005_1.gif

A clockwise

B counterclockwise

C in both directions at the same time

D 50% of the time clockwise and 50% of the time counterclockwise

Q9:
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

Q10: 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

Q11: What are the two main applications for ac?

A direct, pulsating

B electric, magnetic

C power, information

D static, dynamic

Q12: 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

Q13: 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

Q14: What does the CRT oscilloscope display?

A voltage and period

B current and frequency

C rms voltage and current

D frequency and voltage

Q15: 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

Q16: 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

Q17: What voltage will an ac voltmeter display?

A rms

B average

C peak

D peak-to-peak

Q18: 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

Q19: 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

Q20: 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

Q21: What is the rms voltage value of an ac signal whose peak oscilloscope display uses 3 major divisions above the zero setting? (V/cm = 5)

A 5.3 V

B 10.6 V

C 15.0 V

D 21.2 V

Q22: 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

Q23: 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

Q24: 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

Q25: 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

Q26: 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

Q27: 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

Q28: 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

Q29: 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

Q30: 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

Q31: The magnitude that an alternation varies from zero is called its:

A altitude

B amplitude

C attitude

D polarity

Q32: 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

Q33: 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

Q34: 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

Q35: A sine wave has:

A four quadrants

B two alternations

C one period

D all of the above

Q36: 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

Q37: 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

Q38: 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

Q39: What term expresses the frequency of a rectangular wave?

A Hz

B period

C PRF

D PRT

Q40: If the frequency of a radio wave is increased, then its wavelength will:

A increase

B decrease

C remain the same

D cannot tell


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