ELE 100 Final Exam
5 band resistor, value = 82.5K O. First four bands?
Gray - Red - Green - Red
A 56 KO resistor would have what three colors on its first 3 bands?
Green - Blue - Orange
Electric companies base their bills on the unit called
Kilowatt-hour
The ____________ contains the general rules and regulations that contractors, builders and manufacturers must follow for proper installation and routing of wires.
National Electric code
Direction of electron flow in a circuit is always from ____________
Negative to Positive
Superconductors are materials that exhibit _______ resistance to the flow of electricity
Zero
+ and - are called what?
Terminals
Liquid in the cell is called what?
an electrolyte
What is a thermistor?
changes resistance with changes in temperature
Unit of power
Watts
Advantages of digital meters over analog meters are_________________.
display, accuracy and no ambiguity
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?
42 Ohms
What is the current flowing in a 20Ω resistor, when the voltage E=120Volts?
6 Amps
If you have two 3000 ohm resistors in series, what is the total resistance?
6 k ohms
Which of the following choices from highest to lowest capacitances is the correct one?
700 pF < 700 μF < 700 mF < 700 F
A tolerance of ± 20% on a 1000 kΩ resistor is
800 kΩ to 1200 kΩ
White - Brown - Red. What is the value>
9.1K O
A ferromagnetic material is:
A material that shows strong magnetic affects
What would result in greater magnetic field around a coil of wire?
Adding more loops of wire
Naturally occurring magnets in nature are called:
Lodestones
Fuses are made from materials, which have a _____________ melting point.
Low Melting point
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
What is a generator?
Machine that generates electricity to magnetism
Whats a hydrometer?
Measures specific gravity of the acid
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
Safety-devices in electrical circuits are ________________
Circuit-breakers, Fuses and Ground-fault interrupters
The total resistance in a parallel circuit is always greater than the lowest-value branch resistor.
False
Device that produces electricity from chemical reaction?
Electrochemical Cell
What capacitor is polarized?
Electrolytic
At its most basic level, a battery is a can full of chemicals that produces what?
Electrons
The 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
A group of batteries make up a cell.
False
Voltage sources cannot be added in series if they equal values and same polarities
False
Wet conditions decrease the risk of electric shock by lowering the skin resistance.
False
Unit for capacitance
Farads
Ammeters are always connected in parallel in a circuit for measuring the currents.
False
An electromagnet is a permanent magnet.
False
Dry cells are normally used in cars and trucks
False
Whats a capacitor?
Stores energy
If two wires have the same cross-sectional area and made from the same material, the longer wire will have the lesser resistance
False
If two wires have the same cross-sectional area and made from the same material, the longer wire will have the lesser resistance.
False
Insulators offer very less resistance to the flow of electricity.
False
The 4th stripe in five band resistor inidicates tolerance.
False
A circuit has 3.2 A and 110 V. Determine its power.
352 Watts
A voltage of 9V is placed across a 27 Ω resistor. What is the value of the current flowing through it?
.33 Amps
How much current flows in a circuit with a 1.5-volt battery and three 1 ohm resistances (bulbs) in series?
0.5 A
A resistors first three bands are: Brown - Black - Black. What is the value?
10 Ohms (Upside down horseshoe)
If 5 V and 16 V power supplies are connected in series-opposing, what is the total voltage?
11 V
Current through a 100 Ω resistor that is to be used in a circuit is 0.15 A. What is the power being absorbed by the resistor?
2.25 Watts
What is the total resistance of the circuit shown below?
2.5 O
3 bands, Red - Yellow - Black. What is the value?
24 O
If you were to place a 3000 Ω resistor across a 9 volt battery, what would be the power dissipated from this resistor?
27 mW
A 120 Ω and a 40 Ω resistor are in parallel. What is the equivalent resistance?
30 O
Which amongst the following choices listed below is NOT attracted to a magnet.
Aluminum
The smaller the gauge (AWG number) of a wire _______________ is the size of the wire.
Bigger
Ammeter measures what?
Current
What determines if resistor connections are in series, parallel or series-parallel?
Current Flow
Constant flow of electrons in one direction in an electrical circuit is called _____________
DC Current
As additional resistors are connected to a parallel circuit, the total resistance will _______.
Decrease
The first goal(s) to accomplish in analyzing a complex series-parallel circuit is to:
Determine the total resistance and the main current first.
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
Unit of Energy
Joules
Identify the non-renewable energy resource
Nuclear
Chain reaction can be seen in ____________.
Nuclear Power Plant
Atomic Massis deined as the mass of a ___________-
Nucleus
Which law is described by the following equation: V or E = I x R?
Ohm's Law
A magnet made of a material that keeps its magnetism is known as a:
Permanent Magnet
Example of a variable Resisitor
Potentionmeters
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QUIZ 6 NOW
Ohmmeter measures what?
Resistance
What device inhibits/resists the flow of current in a circuit
Resistors
When the current through a coil reverses direction, the magnetic field around the coil _____.
Reverses its direction
How do you make an electromagnet?
Run current through a wire wrapped around an iron rod
Which of the following statements describes a good solder joint?
Smooth and shiny
When the plate area of a capacitor increases,
The capacitance increases
An object is not magnetized if:
The grouping of atoms are scattered
The voltage across any branch of a parallel circuit is_____________.
The same as other parallel elements
Why is copper a good conductor of electricity?
There are many free electrons present
Soft solder is an alloy of ______________
Tin & Lead
All electrical circuits have to be grounded
True
Analog and digital are most common
True
Grounding involves providing a conductor to carry current into the ground rather than into a body
True
It takes less than 1 A of current to kill you if it travels through your heart.
True
Tungsten is used to make light bulbs
True
Voltmeters and Ammeters are polarized instruments.
True
When using an analog meter to measure unknown currents or voltages, always start with the range selector switch set at the highest position.
True
What color is never used?
Turquoise
Unit of Voltage
Volts
3 best insulators
rubber, mica, plastic
3 factors that affect capacitance
surface area, distance between plates, and insulating material
