NEIEP 600 Final Exam Review: Questions &
Answers(Solved)
when a cam or vane is moved close to a magnetic levleing switch what occurs? -
ANSWERthe switch changes its satate
what is meant by the normal state of relay contacts? - ANSWERcontact state without
current applied to the coil
what type of wave form is generated by two pole ac generator in one complete
revolution? - ANSWERone full AC cycle
what defines the the period of a ac waveform ? - ANSWERthe time it takes to
complete one full cycle .
what is the period of a 120 hz - ANSWER.00833 seconds
a sine wave beginning at 0 degrees will reach positive and negative peaks at what
two points ? - ANSWER90 and 270 degrees
what is it meant by the term peak to peak voltage ? - ANSWERvoltage between
positive and negative peaks
the expression 0.636Xpeak voltage best describes what? - ANSWERvoltage or current
average
what best describes the term AC effective voltage ? - ANSWERthe AC voltage
required to produce the same power as a DC voltage
what is the peak voltage of a waveform with 480 VAC RMS? - ANSWER679 volts
what effect an inductor has on current flow ? - ANSWERit opposes change
what is the secondary voltage of a 5 to 1 step down transformormer whith a primary
voltage of 125 volts - ANSWER25 volts
the primary of a 5 to 1 step down transformer has 1 amp . what is the secondary
current? - ANSWER5 amps
how can three phase voltage be stepped down using transformer ? - ANSWERby
using a three phase transformer or three single phase transformers
in capacitors , what is the purpose of the dielectric ? - ANSWERprevent acring within
the capacitor
, which of the following is true about capacitors in ac CUIRCUITS .? - ANSWERcurrent
leads voltage all the time
what describes a capacitor's ability to store an electrical charge -
ANSWERcapacitance
what is the time constant for a circuit with 150 k ohms and 2 microfarad capacitor? -
ANSWER.3 seconds
what describes a capacitor's ability to store an electrical charge -
ANSWERcapacitance
which of the following satements is correct about polorized electrolytic capacitors -
ANSWERvoltage polarity must be correct
what happends in a cuircuit , when the capacitor voltage equals the source voltage ?
- ANSWERcurrent flow stops in the cuircuit
in a dc cuircuit when capacitors are present , when is current maximum ? -
ANSWERthe instant when power is applied
if a cuircuit has a capacitor of 5 micro farads and a source voltage of 120 volts DC
through a resistant of 200 k , how long will it take to fully charge? - ANSWER5
seconds
what is the definition of a time constant of a capacitor ? - ANSWERthe time it takes
for the capacitor to charge to 63.2 % of fthe applied voltage
which unit of measure is used to measure capacitance ? - ANSWERFArads
what does the increase of plate area do in a capacitor ? - ANSWERincreases
capacitance
if two capacitors in parallel have equal reactance of 40 ohms what is the total
reactance ? - ANSWER20 ohms
if frequency is increased in a capacitive cuircuit , what will happen? -
ANSWERcapacitive reactance will decrease
what is the unit of inductance ? - ANSWERhenry
How many degrees does AC in a purely inductive circuit lag voltage by? - ANSWER90
degrees
How is an air coil magnetized? - ANSWERcurrent is increased it eventually reaches
saturation
Answers(Solved)
when a cam or vane is moved close to a magnetic levleing switch what occurs? -
ANSWERthe switch changes its satate
what is meant by the normal state of relay contacts? - ANSWERcontact state without
current applied to the coil
what type of wave form is generated by two pole ac generator in one complete
revolution? - ANSWERone full AC cycle
what defines the the period of a ac waveform ? - ANSWERthe time it takes to
complete one full cycle .
what is the period of a 120 hz - ANSWER.00833 seconds
a sine wave beginning at 0 degrees will reach positive and negative peaks at what
two points ? - ANSWER90 and 270 degrees
what is it meant by the term peak to peak voltage ? - ANSWERvoltage between
positive and negative peaks
the expression 0.636Xpeak voltage best describes what? - ANSWERvoltage or current
average
what best describes the term AC effective voltage ? - ANSWERthe AC voltage
required to produce the same power as a DC voltage
what is the peak voltage of a waveform with 480 VAC RMS? - ANSWER679 volts
what effect an inductor has on current flow ? - ANSWERit opposes change
what is the secondary voltage of a 5 to 1 step down transformormer whith a primary
voltage of 125 volts - ANSWER25 volts
the primary of a 5 to 1 step down transformer has 1 amp . what is the secondary
current? - ANSWER5 amps
how can three phase voltage be stepped down using transformer ? - ANSWERby
using a three phase transformer or three single phase transformers
in capacitors , what is the purpose of the dielectric ? - ANSWERprevent acring within
the capacitor
, which of the following is true about capacitors in ac CUIRCUITS .? - ANSWERcurrent
leads voltage all the time
what describes a capacitor's ability to store an electrical charge -
ANSWERcapacitance
what is the time constant for a circuit with 150 k ohms and 2 microfarad capacitor? -
ANSWER.3 seconds
what describes a capacitor's ability to store an electrical charge -
ANSWERcapacitance
which of the following satements is correct about polorized electrolytic capacitors -
ANSWERvoltage polarity must be correct
what happends in a cuircuit , when the capacitor voltage equals the source voltage ?
- ANSWERcurrent flow stops in the cuircuit
in a dc cuircuit when capacitors are present , when is current maximum ? -
ANSWERthe instant when power is applied
if a cuircuit has a capacitor of 5 micro farads and a source voltage of 120 volts DC
through a resistant of 200 k , how long will it take to fully charge? - ANSWER5
seconds
what is the definition of a time constant of a capacitor ? - ANSWERthe time it takes
for the capacitor to charge to 63.2 % of fthe applied voltage
which unit of measure is used to measure capacitance ? - ANSWERFArads
what does the increase of plate area do in a capacitor ? - ANSWERincreases
capacitance
if two capacitors in parallel have equal reactance of 40 ohms what is the total
reactance ? - ANSWER20 ohms
if frequency is increased in a capacitive cuircuit , what will happen? -
ANSWERcapacitive reactance will decrease
what is the unit of inductance ? - ANSWERhenry
How many degrees does AC in a purely inductive circuit lag voltage by? - ANSWER90
degrees
How is an air coil magnetized? - ANSWERcurrent is increased it eventually reaches
saturation
