Basic Electrical Theory final review 2.0
If the wiper is moved to the bottom of the resistor, the voltmeter will indicate a value of how many volts?
0
In a parallel circuit, the supply voltage is 120 V, 60 Hz. The resistance is 30 Ω and the inductive reactance is 40 Ω. What is the value of the inductor?
0.106 H
A three-branch parallel circuit has resistors of 27 Ω, 56 Ω, and 15 Ω. What is the total resistance?
8.23 Ω
What is the unit of measurement for inductance?
Henry (H)
Increasing the surface area of the plates will cause the capacitance of a capacitor to _____.
increase
How many amperes is present in a 20-volt battery with a 30-ohm resistor?
0.67
A parallel circuit composed of a 150 Ω and a 270 Ω resistor has a voltage of 120 V. What is the current in the 150 Ω resistor?
0.8 A
A series circuit has two resistors that dissipate 10 W and 15 W, respectively. What is the total power dissipation of the circuit?
25 W
In the diagram of connected batteries, what is the total voltage?
48 V
A(n) _____________ battery is a lead-acid battery that does not spill sulfate or degrade like the common flooded cell battery
Absorbed Glass Mat (AGM)
What letter symbolizes the farad?
F
What is produced when electrons move to a lower orbit and produce a photon?
Light
Refer to the diagram. Through what must all the current in the circuit flow?
R1
Refer to the diagram. At what junction point does the current split?
R2 and R3
Matter has mass and occupies space.
True
Which of the following is an example of an insulator?
Wood
What meter must NEVER be connected to a circuit when the circuit power is turned on?
an ohmmeter
Static electricity refers to electrons that _____ moving.
are not
Several cells connected together that produce voltage are called a _____.
battery
The word _____ is often used in reference to a single cell.
battery
What is a device that opposes a change of voltage?
capacitor
Each complete waveform of 360° is called a _____.
cycle
A voltage _____ is used to provide different voltages between certain points in a circuit.
divider
What is used to represent fixed and variable resistors?
electrical schematics
In the English system of measure, magnetic strength is measured in terms of _____.
flux density
The number of cycles completed in 1 second is called a _____.
frequency
When using the oscilloscope, which control adjusts the brightness of the trace?
intensity
When the connection of a meter to the circuit changes the entire circuit operation, this is known as the _____ effect.
loading
The unit of resistance to current flow is the _____.
ohm
Square waves are generally produced by electronic devices called _____.
oscillators
What circuit does the image represent?
parallel
A temperature coefficient that is __________ indicates the capacitor will increase its capacitance with an increase in temperature.
positive
What causes a wire to become warm when current flows through it?
resistance
The semiconductor material used as a coating on copy machine drums is _____.
selenium
Rotating machines normally produce a waveform called a _____ wave.
sine
What is the most common of all AC waveforms?
sine
What is another term for electromotive force (EMF)?
voltage
What can be adjusted to provide any value of voltage between 12 and 0 volts?
wiper
Refer to the diagram and solve using the values provided. R1 = 240 Ω, R2 = 300 Ω, and R3 = 1200 Ω. What is the resistance between A and B?
480 Ω
The time required for current in an inductor to reach its full Ohm's law value is called the _____ time constant.
R-L
In the combination circuit, which two paths are parallel?
R1 and R2, R3 and R4
A lightning protection device that is grounded at one end, with the other end close to but not touching the object to be protected, is called a lightning _____.
arrestor
Parallel circuits are also called _____.
current dividers
What type of magnet depends on flowing current to produce a magnetic field?
electromagnet
On a ceramic capacitor, what does the wide band indicate?
temperature coefficient
A two-resistor series circuit has an applied voltage of 100 V. The voltage across one of the resistors is 40 V. What is the voltage across the other resistor?
60V
Any time an electric current flows through what component is a magnetic field created around the conductor?
conductor
Capacitors charge and discharge at a(n) _____ rate.
exponential
Exponential curves are always divided into _____ time constants.
five
Magnetic lines of force are referred to as _____.
flux
When measuring for resistance with a Wheatstone bridge, what is used to measure the voltage between points?
galvanometer
In some capacitors, there is a small amount of current that flows from one plate, through the dielectric material to the other plate. This current is called _____ current.
leakage
What type of AC waveform features voltage rising at a constant rate with respect to time?
linear
Which of the following is also called an Edison battery?
nickel-iron
Bringing a charged test object near the ball of a charged electroscope causes the leaves to move closer together. This indicates that the test object charge is the _____ polarity as the electroscope charge.
opposite
A capacitor is constructed by separating two metal conductors known as _____ with an insulating material known as a(n) _____.
plates; dielectric
If a voltage is being induced into a conductor by electromagnetic induction, reversing the direction of motion of the conductor will _____.
reverse the polarity of the induced voltage
When a magnetic material's molecules are all lined up; and increases in current flow no longer cause increases in magnetic field strength, the material has reached _____.
saturation
When using the oscilloscope to interpret the _____________ on display, it is important to remember that the display shows the voltage with respect to time.
waveforms