# 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

## A sine wave has:

• B. two alternations
• C. one period
• D. all of the above

• A. 90°
• B.
• C. –90°
• D. 360°

## 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

## 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

## AC effective voltage is named:

• A. average
• B. peak
• C. peak-to-peak
• D. root mean square

• A. 5.38 ms
• B. 10.8 ms
• C. 53.8 ms
• D. 108 ms

• A. 14.14 mV
• B. 35.4 mV
• C. 63.7 mV
• D. 70.7 mV

• A. 159.0 mV
• B. 318.5 mV
• C. 353.5 mV
• D. 451.0 mV

• A. 100 Hz
• B. 1000 Hz
• C. 10 kHz
• D. 100 kHz

## 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

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

• A. increase
• B. decrease
• C. remain the same
• D. cannot tell

## 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

## 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

## 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

## 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

## 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

## 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

## 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

## 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

• A. lambda
• B. theta
• C. omega
• D. delta

• A. altitude
• B. amplitude
• C. attitude
• D. polarity

## 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

## 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

## What are the two main applications for ac?

• A. direct, pulsating
• B. electric, magnetic
• C. power, information
• D. static, dynamic

## What does the CRT oscilloscope display?

• A. voltage and period
• B. current and frequency
• C. rms voltage and current
• D. frequency and voltage

• A. 3.82 V
• B. 4.24 V
• C. 7.64 V
• D. 9.42 V

## 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

## 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

• A. 163 V
• B. 230 V
• C. 325 V
• D. 480 V

• A. 158 V
• B. 164 V
• C. 82 V
• D. 79 V

• A. 14 mA
• B. 28 mA
• C. 40 mA
• D. 57 mA

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

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

• A. 50 ms
• B. 100 ms
• C. 150 ms
• D. 200 ms

• A. Hz
• B. period
• C. PRF
• D. PRT

## What voltage will an ac voltmeter display?

• A. rms
• B. average
• C. peak
• D. peak-to-peak

## 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

## 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