NIU ELE 100 Online & In- Class Quizzes 1-6
What tolerance does a silver band represent?
10%
A resistor's first three color bands are: brown, black, and black. What is its value?
10Ω
If 5V and 16V power supplies are connected in series-opposing, what is the total voltage?
11V
If the first resistor opened in the circuit of the previous problem, what would the total current be?
128mA
How do you calculate the voltage drop across each resistor in series in a circuit?
Find the total resistance, use it to calculate the current, and then use those values to find the voltage drop for each resistor.
How do you calculate the primary voltage applied to a transformer?
Find the voltage for the side of the coil ratio where current and resistance are given, and then use the coil ratio to find the voltage of the other side
MOSFET stands for
Metal Oxide Semiconductor Field Effect Transistor
Who discovered the principle of electromagnetic generators?
Michael Faraday
Which law is described by the following equation: V or E = I x R?
Ohm's Law
The formula for power is
P=IxE
The unit for capacitance is
farads
If a continuity tester does not light up, it means that the fuse is
broken
T/F: Voltage sources cannot be added in series if they have equal values and the same polarities.
false
T/F: Wet conditions decrease the risk of electric shock by lowering the skin resistance.
false
T/F: When you break a magnet in two, you can separate the two poles.
false
The machine that generates electricity from magnetism is called a
generator
A five-band color coded resistor has a value equal to 82.5 kΩ. What are the colors of the first four bands/
gray, red, green, red
A 56 KΩ resistor would have which colors on it's first 3 bands?
green, blue, orange
Identify the non-renewable energy resource.
nuclear
Electrical generators perform which kind of energy conversion?
mechanical energy to electrical energy
materials that allow electricity to flow through them easily are called
metals
A parallel circuit differs from a series circuit in that a parallel circuit has
more than one path for current flow
The machine that converts electrical energy to mechanical energy is called a
motor
Direction of electron flow in a circuit is always from
negative to positive
How will an open resistor affect a series circuit?
no current will flow in the circuit
Chain reaction can be seen in
nuclear power plant
Atomic mass is defined as the mass of a/an ___________ of an atom.
nucleus
Which of these colors is NOT used in the resistor value color code?
turquoise
How can you show that electricity creates a magnetic field?
use a compass near a wire with current flowing through it
A rheostat is another name for a
variable resistor
A voltmeter is used to measure the
voltage
A series network of resistors used to provide different voltages from a single source of energy is called a
voltage divider
The unit of voltage is
volts
The unit of power is
watts
Tools used to remove insulation from wires are:
wire strippers and knives
A 47 KΩ resistor woud have which colors on its first 3 bands?
yellow, violet, orange
Superconductors are materials that exhibit ___________ resistance to the flow of electricity.
zero
T/F: A group of batteries make up a cell.
false
T/F: A light emitting diode absorbs light to generate electricity.
false
T/F: A primary cell can be recharged.
false
T/F: A thermocouple consists of two similar metals bonded together.
false
T/F: Ammeters are always connected in parallel in a circuit for measuring the currents.
false
T/F: An electromagnet is a permanent magnet.
false
T/F: Atomic number is defined as the number of neutrons in an atom.
false
T/F: Current does not flow in a forward biased diode.
false
T/F: Diodes conduct in both directions.
false
T/F: Dry cells are normally used in cars and trucks.
false
T/F: If two wires have the same cross-sectional area and are made from the same material, the longer wire will have the lesser resistance.
false
T/F: Insulators offer very little resistance to the flow of electricity.
false
T/F: Integrated circuits are devices made up of only resistors.
false
T/F: Like charges attract each other.
false
T/F: Resistors connected in series do not share the same current.
false
T/F: Solid wire is more flexible than stranded wire.
false
T/F: Step-up transformers are located near to end user.
false
T/F: The fourth stripe in the five band color coded resistors indicates the tolerance.
false
T/F: The heavier the doping in a semiconductor, the lower the conductivity.
false
T/F: The magnetic field strength is the weakest at the poles and strongest along the length of the magnet.
false
T/F: The total resistance in a parallel circuit is always greater than the lowest-value branch resistor.
false
T/F: Two particles with different charges will repel or drive away from each other.
false
Which wire type is best suited for use as a lamp cord?
stranded
How do you calculate the total voltage when the power supplies are connected in series-opposing?
subtract
The three factors that affect capacitance are:
surface area, distance between the plates, and the insulating material
What is the device that is used to open and close a circuit?
switch
Devices used to open and close circuits without the inconvenience of disconnecting and reconnecting wires are called
switches
A transistor is used for
switching voltages and currents, amplifying small signals into large currents
Thermocouple is used to measure the
temperature
The areas of a battery that are marked positive (+) and negative (-) are called
terminals
When the plate area of a capacitor increases;
the capacitance increases
An object is not magnetized if
the groupings of atoms are scattered
What is meant by a step-down transformer?
the output voltage is smaller than the input voltage
Electromagnetic induction is a term used to describe
the production of electric potential due to change in magnetic flux
If the circuit is in parallel, the voltage is ___________ for each branch.
the same
If the circuit is in series, the current is ___________ across all resistors.
the same
The voltage across any branch of a parallel circuit is
the same as the other parallel elements
If replacement capacitors are not available, you should substitute it with a capacitor that has
the same rating, but higher working voltage
The total current in a parallel circuit is equal to
the sum of the current of each branch
The total capacitance of capacitors connected in parallel is
the sum of the individual capacitors.
Which size wire is larger in diameter: #10 or #24?
#10
Express 2.01 x 10^-4 in its normal number notation.
0.000201
Convert 300 µAmperes to Amperes.
0.0003 Amperes
If you were to place a 3000 Ω resistor across a 9 volt battery, what would be the power dissipated from this resistor?
0.027W or 27mW
A voltage of 9V is placed across a 27Ω resistor. What is the value of the current flowing through it?
0.33 Amps
How much current flows in a circuit with a 1.5 volt battery and three 1 ohm resistances (bulbs) in series?
0.5A
KΩ multiplies Ω by
1,000
The term "milliamp" means ___________ of an amp.
1/1000th
The formula for total capacitance of capacitors connected in series
1/CT=1/C1+1/C2+1/C3+...
The formula for total resistance for resistors in parallel is
1/RT=1/R1+1/R2+1/R3+...
What is the total current in a parallel circuit with branches with currents of 42mA and 128 mA?
170mA
Determine the amount of power absorbed in a circuit if a 6V battery is used and a 3A of current is flowing in the circuit?
18 Watts
What is the current flowing through each of the two 10Ω resistors in problem #16?
1A, 1A
Current through a 100Ω resistor that is to be used in a circuit is 0.15A. What is the power being absorbed by the resistor?
2.25 Watts
If four 10Ω resistors are in parallel, the total resistance is
2.5Ω
A circuit has a current of 2.15 A flowing through it. How many milliamps (mA) does that equal?
2150 mA
A resistor's first three color bands are: red, yellow, and black. What is its value?
24Ω
If a circuit has 12V and 3 resistors in series equal to 1Ω, 2Ω, and 3Ω, what is the current flowing in the circuit?
2A
mF moves the decimal point
3 places forward
A transistor is a
3-terminal device
A 120Ω and a 40Ω resistor are in parallel. What is the equivalent resistance?
30Ω
A circuit has 3.2A and 110V. Determine its power.
352 Watts
A transformer which has 1380 turns in its primary coil is to be used to convert the mains voltage of 230 V to operate a 6 V bulb. How many turns should the secondary coil of this transformer have?
36 turns
The voltage across the secondary coil of a transformer with a primary coil with 180 turns, a primary voltage of 12V, and a secondary coil with 540 turns is
36V
How much current flows in a circuit with a 18-volt battery and six 1 ohm resistors (bulbs) in series?
3A
A series circuit contains five resistors. The total resistance for the circuit is 186Ω. The values of four of the resistors are:20Ω,14Ω,10Ω and 100Ω. What is the value of fifth resistor?
42Ω
If a circuit has 12V and 3 resistors in series equal to 1Ω, 2Ω, and 3Ω, what is the voltage drop across each resistor in the circuit?
4V, 6V, and 2V
What tolerance does a gold band represent?
5%
Convert 540,000,000 into its corresponding scientific notation.
54 x 10^7
What is the current flowing in a 20Ω resistor, when the voltage E=120 volts?
6 amps
µAmperes moves the decimal point
6 places forward
AC frequency in the US is
60 Hz
If you have two 3000 ohm resistors in series, what is the total resistance?
6kΩ
Which of the following choices from highest to lowest capacitances is the correct one?
700 pF<700 µF<700mF<700F
A tolerance of ± 20% on a 1000 kΩ resistor is
800 kΩ to 1200 kΩ
What is the total resistance in a circuit which contains 20Ω, 20Ω and 40Ω resistors in series?
80Ω
A resistor's first three color bands are: white, brown, and red. What is its value?
9.1kΩ
What is the primary voltage applied to a transformer with a 15 ohm resistor, a 1.2A current, and a 5:1 coil ratio?
90V`
Convert 95KΩ to Ω.
95,000Ω
What are the effects of moving a closed wire loop through a magnetic field?
A voltage is induced in the wire, a current is induced in the wire, and the polarity of the voltage across the wire depends on the direction of motion
Will a transformer work with direct current (DC) or alternating current (AC)?
AC only
How do you find the current flowing through resistors connected in parallel?
Add the resistances and then use each individual resistance and that total to create a ratio, then multiply the ratio by the main current.
What is an acronym for the order of the colors on a resistor's bands?
BBROYGBVGW
Constant flow of electrons in one direction in an electrical circuit is called a
DC current
What is Ohm's law?
E=IR
Put the sub-units of F in order from least to greatest.
F<mF<µF<pF
What causes magnetism?
Movement of electrons around the nucleus and spinning around their own axis.
The ___________ contains the general rules and regulations that contractors, builders, and manufacturers must follow for proper installation and routing of wires.
National Electric Code
For the circuit shown here, which statement is true?
R5 is in parallel with R6 and R7 (which are in series)
What is the formula for total resistance in series?
RT=R1+R2+R3+...
What happens when you turn off the current in an electromagnet?
The magnetism is turned off
Given a series circuit containing resistors of different values, which statement is not true?
The voltage drop across each resistor is the same.
T/F: Tungsten is used to make light-bulb filaments.
True
Which of the following best describes the difference between wet cells and dry cells?
Wet cells have a liquid electrolyte, while in dry cells the electrolyte is a moist paste.
A ferromagnetic material is
a material that shows strong magnetic effects
What would result in greater magnetic field around a coil of wire?
adding more loops of wire
In a series connected circuit with 100 Christmas bulbs, if one bulb burns out, what happens to the remaining bulbs?
all bulbs turn off
AC generators are also called ___________, since they produce an alternating current.
alternators
Which amongst the following choices listed is NOT attracted to a magnet?
aluminum
The positive end of a diode is called the ___________ and the negative end is called the ___________.
anode, cathode
You can tell if an object is magnetic if the groupings of atoms
are lined up in the same direction
The smaller the gauge (AWG number) of a wire the ___________ the size of the wire.
bigger
In what order from 0-9 do the colors go on a resistor's bands?
black, brown, red, orange, yellow, green, blue, violet, gray, white
Commonly used transistor/s is/are
both A & B
A thermistor
changes resistance with changes in temperature
Safety-devices in electrical circuits are
circuit breakers, fuses, and ground-fault interrupters
An ammeter measures
current
What determines if resistor connections are in series, parallel, or series-parallel?
current flow
If the resistance in a circuit decreases while the voltage stays the same, what happens to the current?
current increases
As additional resistors are connected to a parallel circuit, the total resistance will
decrease
Increasing the number of turns of wire on the secondary of a transformer will
decrease the secondary current and increase the primary current
The first goal(s) to accomplish in analyzing a complex series-parallel circuit is to
determine the total resistance and the main current first
If the circuit is in series, the voltage drop is ___________ across all resistors.
different
If the circuit is in parallel, the current ___________ for each branch, depending on
different, the resistance of the individual branches
Never touch a capacitor without first ___________ it.
discharging
Advantages of digital meters over analog meters are
display, accuracy, and no ambiguity
What is the most common electric shock-related injury?
electrical burns
The device that produces electricity from chemical reaction is called an
electrochemical cell
Death caused by an electric shock is called
electrocution
Liquid in the cell is called an
electrolyte
Which of the following capacitors is polarized?
electrolytic
___________ is the generation of current due to relative motion between a wire and a magnetic field.
electromagnetic induction
An N-type semiconductor has an excess of
electrons
At its most basic level, a battery is a can full of chemicals that produces
electrons
The terminals of a BJT transistor are called
emitter, base, and collector
The (4) basic parts of a circuit are:
energy source, switch, conductive path, and load
What is it that does not affect the amount of current flow induced by magnetism?
environment
T/F: A car battery uses zinc paste as its electrolyte.
false
The unit of inductance is
henry
The faster the coil of a generator rotates through the magnetic field, the
higher the output voltage
A P-type semiconductor has an excess of
holes
A(n) ___________ is used to measure the specific gravity of the acid used in a storage battery.
hydrometer
If the voltage in an electrical circuit containing a lightbulb is increased, what happens to the brightness of the bulb?
increases
Atoms that lose or gain electrons become
ions
What are atoms of the same element having the same number of protons but different number of neutrons called?
isotopes
What happens to total resistance in a circuit with parallel resistors if one of them opens?
it increases
The unit of energy is
joules
Electric companies base their bills on a unit called the
kilowatt-hour
A photovoltaic material is one which converts
light energy into electricity
Naturally occurring magnets in nature are called
lodestones
Fuses are made from materials which have a ___________ melting point.
low
If you measured your body resistance while your palms were damp, your ohmmeter would get a ___________ reading than if measured with your palms dry.
lower
Soldering is the process of joining metals using another metal that has a ___________ melting point.
lower
This is a force where objects are attracted or repelled to one another
magnetism
One way to stop the flow of electrons is to ___________ the circuit.
open
A voltmeter is always connected in ___________ with the other components in an electrical circuit.
parallel
A magnet made of a material that keeps its magnetism is known as a
permanent magnet
Which is an example of a variable resistor?
potentiometers
Piezoelectricity is electricity generated from
pressure
What is the equation to calculate the primary or secondary voltage/number of turns in a step-up/step-down transformer?
primary # of turns/secondary # of turns=primary voltage/secondary voltage (NP/NS=VP/VS)
One of the materials used to produce electricity by pressure is
quartz
Converting AC to DC is accomplished by the process of
rectification
If two magnets were in this order: NS SN, they would
repel
An ohmmeter measures
resistance
What device inhibits/resists the flow of current in a circuit?
resistor
When the current through a coil reverses direction, the magnetic field around the coil
reverses its direction
The best insulators are:
rubber, mica, and plastic
How do you make an electromagnet?
run current through a wire wrapped around an iron rod
Nickel-Cadmium, Lithium ion, and nickel-metal hydride cells are
secondary cells
An ammeter is always connected in ___________ with the other components in an electrical circuit.
series
Which of the following statements describes a good solder joint?
shiny, smooth, and a concave fillet
Identify the semiconductor.
silicon
An integrated circuit is made on a ___________ piece of silicon called the chip.
single
Electrical soldering is also called ___________ soldering.
soft
Devices used to convert solar energy to electricity are called
solar cells
A soldering iron or a soldering gun tip is tinned by coating its surfaces with
solder
Choose the magnetic materials.
steel and iron
In a transformer, the primary coil has twice as many loops as the secondary coil. This is a ___________ transformer.
step-down
A capacitor
stores energy or charges
Copper is a good conductor of electricity because
there are many free electrons present in this metal
Soft solder is an alloy of ___________ and ___________.
tin, lead
The last stripe on a color coded resistor indicates the
tolerance
What do the gold or silver bands on a resistor represent?
tolerance
T/F: A P-type semiconductor material has a shortage of electrons with vacancies called holes.
true
T/F: A schematic is used instead of a complex, detailed drawing of an electrical circuit.
true
T/F: According to the principle of electromagnetic induction, a generator produces voltage when there is a changing magnetic field.
true
T/F: Addition of impurities to the pure semiconductor is called doping.
true
T/F: All electrical circuits have to be grounded.
true
T/F: An inductor is an element which is a coil of wire wound around an iron core.
true
T/F: Conductance is the reciprocal of resistance in a circuit.
true
T/F: For a transformer, power is conserved at the primary (input) and at the secondary (output).
true
T/F: Grounding involves providing a conductor to carry current into the ground rather than into a body.
true
T/F: If resistors in parallel have equal value, their total resistance is half the value of one resistor.
true
T/F: If you add up the currents of each resistor for resistors in parallel, the total is equal to the main current of the circuit.
true
T/F: Increasing the current flowing through a coil increases the magnetic field strength.
true
T/F: Inductors add up like resistors in series and parallel.
true
T/F: It is dangerous to charge a non-rechargeable battery.
true
T/F: It takes less than 1A of current to kill you if it travels through your heart.
true
T/F: It's always important to replace a blown out fuse with the proper one.
true
T/F: Magnetic flux flows from the North Pole to the South Pole.
true
T/F: Materials that lose magnetism quickly are called "soft magnets".
true
T/F: Nichrome is used as a heating element.
true
T/F: Organic LED's give off very nice vibrant colors and are flexible.
true
T/F: Rosin core solder should be used for all electrical soldering.
true
T/F: Semiconductors are materials that have conductivity in between conductors and insulators.
true
T/F: The operation of an electrical generator relies on electromagnetic induction.
true
T/F: The size of an integrated circuit is part of the reason for the importance of ICs in electronics.
true
T/F: The two basic multi-meters are analog and digital.
true
T/F: The voltage drops of resistors in series equal the total voltage/starting voltage.
true
T/F: Wearing safety glasses is very important while soldering.
true
T/F: When using an analog meter to measure unknown currents or voltages, always start with the range selector switch set at the highest position.
true
