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WorksheetsAlternating Current
Total questions: 36
Worksheet time: 18mins
The working voltage in an ac circuit should be
equal to the highest applied voltage
at least 20 percent greater than the highest applied voltage
at least 50 percent greater than the highest applied voltage
The term that describes the combined resistive forces in an ac circuit is
resistance
reactance
impedance
The basis for transformer operation in the use of alternating current is mutual
inductance
capacitance
reactance
The opposition offered by a coil to the flow of alternating current is called (disregard resistance)
impedance
reluctance
inductive reactance
An increase in which of the following factors will cause an increase in the inductive reactance of a circuit?
Inductance and frequency
Resistance and voltage
Resistance and capacitive reactance
Capacitors are sometimes used in DC circuits to
counteract inductive reactance at specific locations
smooth out slight pulsations in current/voltage
assist in stepping voltage and current up and/or down
In an ac circuit, the effective voltage is
equal to the maximum instantaneous voltage
greater than the maximum instantaneous voltage
less than the maximum instantaneous voltage
The amount of electricity a capacitor can store is directly proportional to the
distance between the plates and inversely proportional to the plate area
plate area and is not affected by the distance between the plates
plate area and inversely proportional to the distance between the plates
Unless otherwise specigied, any values given for current or voltage in an AC circuit are assumed to be
instantaneous values
effective values
maximum values
The potential difference between two conductors which are insulated from each other is measured in
volts
amperes
coulombs
When calculating power in a reactive or inductive AC circuit, the true power is
more than apparent power
less than the apparent power in a reactive circuit and more than the apparent power in an inductive circuit
less than the apparent power
Which of the following are commonly used as rectifiers in electrical circuits?
Anodes
Cathodes
Diodes
Diodes are used in electrical power supply circuits primarily as
switches
rectifiers
relays
Transfer of electrical energy from one circuit to another without the aid of electrical connections
is called induction
is called capacitance
can cause excessive arcing and heat, and as a result is practical for use only with low voltages/amperages
Which of these will cause the resistance of a conductor to decrease?
Decrease the length of the cross-sectional area
Decrease the length or increase the cross-sectional area
Increase the length or decrease the cross-sectional area
Through which material will magnetic lines of force pass the most readily?
Copper
Iron
Aluminum
The electrical symbol represented in the figure is a variable
inductor
resistor
capacitor
Typical application for zener diodes is as
full-wave rectifiers
half-wave rectifiers
voltage regulators
The symbol for impedance is
L
X
Z
A current which periodically changes direction and magnitude is known as
Direct Current
Alternating Current
Pulsating DC
An instrument that displays AC waveforms graphically is a
Ammeter
Wave meter
Oscilloscope
When the varying magnetic field of an inductor induces a voltage into a nearby inductor, it is called
Mutual inductance
Self Inductance
Mutual Capacitance
The unit of measurement of the ability of a capacitor to store an electrical charge is the
Farad
Ohm
Amp
The opposition to the flow of alternating current offered by a capacitor is called
Capacitance
Inductive Reactance
Capacitive Reactance
What is the phase relationship between the current and voltage in a purely capacitive circuit?
The current leads the voltage by 90°
The current lags the voltage by 90°
The current leads the voltage by 0°
When capacitors are connected in parallel, the total capacitance is equal to
The sum of the reciprocals of the capacitances
The sum of the capacitances divided by the number of capacitors
The sum of the capacitances
The opposition to current flow offered by an inductor in an AC circuit is
Inductance
Capacitive Reactance
Inductive Reactance
Inductance in an AC circuit causes the current to
Lead the voltage
Lag the voltage
Remain in phase with the voltage
The efficiency of power in an AC circuit is expressed by what term?
True power
Apparent Power
Power factor
In a transformer with two windings, which one is the primary? The winding
with the least turns
connected to the source
connected to the load
Two advantages of AC over DC are:
Easy to generate, easy to change voltage and current values
A comes before
D in the alphabet
Don't know because I did not study this
The waveform of alternating current produced by a rotating generator is called a
Sine wave
Big wave
Don't care because I hate this class
What is one complete sequence of voltage or current changes from zero to a positive peak to zero, then through a negative peak and back to zero?
Cycle
A bunch of electrical terms I don't know
Who cares?
What is one-half of an AC cycle?
Alternation
Altercation
Don't know because I did not study this
The time required for one cycle of events to occur is known as
Period
Headache
Mind-numbing
The time constant of an R-L circuit is found using what formula?
TC=L/R
ABC=123
TC=R/L
