ELE 100 Final
How much current flows in a circuit with a 1.5-volt battery and three 1 ohm resistance (bulbs) in series
0.5 A
A voltmeter is a meter used to measure the
Voltage
Which of the following best describes the differences between wet cells and dry cells
Wet cells have a liquid electrolyte, while in dry cells the electrolyte is a moist paste
Tools used to remove insulation from wires.
Wire strippers and Knives
A 47 K Ω resistor would have which colors on its first 3 bands
Yellow, Violet, Orange
A 470 k Ω resistor would have which colors in its first three bands?
Yellow, Violet, Yellow
Superconductors are materials that exhibit _________ resistance to the flow of electricity
Zero
What would induce a greater electric current in a wire?
adding more loops of wire
What would result in greater magnetic field around a coil of wire
adding more loops of wire
AC generators are also called _______________, since they produce an alternating current.
alternators
Liquid in the cell is called
an electrolyte
Ammeter measures
current
Electromagnetic induction is a term used to describe
production of electric potential due to change in magnetic flux
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
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
An ammeter is always connected in ______________ with the other components in an electrical circuit.
series
Which sized wire is larger in diameter - #10 or #24?
#10
Express 2.01x10-4 in its normal number notation.
0.000201
A voltage of 9V is placed across a 27 Ω resistor. What is the value of the current flowing through it?
0.33 Amps
A circuit has three 30 Ω resistors connected in parallel. A voltage source of 30 V is connected across this parallel combination of resistors. What is the current flowing through all three resistors
1A, 1A, 1A
Determine the amount of power absorbed in a circuit if a 6V battery is used and a 3A current is flowing in the circuit
18 watts
How do you find the total resistance in a parallel circuit
Total resistance art is the reciprocal of the sum of the reciprocal of all the individuals resistances. 1/Rt = 1/R1 + 1/R2 + 1/R3
A P-type semiconductor material has a shortage of electrons with vaccines called holes
True
A capacitor stores energey
True
According to principal of electro-magnetic induction, Generator produces voltage
True
Addition of impurities to the pure semiconductor is called Doping.
True
All electrical circuits have to be grounded
True
Increasing the current flowing through a coil increases the magnetic field strength
True
Is it dangerous to charge a non-rechargeable battery
True
Magnetic flux flows from the North Pole to the South Pole.
True
Materials that loose magnetism quickly are called "soft magnets"
True
Rosin core solder should be used for all electrical soldering
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
Objects with like charges repel and unlike charges attract. The girl's hair and the comb have
Unlike charges
How can you show that electricity creates a magnetic field
Use a compass near a wire with current flowing through it
A resistor's first three color bands are; brown, black, and orange. What is its value
10 KΩ
A circuit had three 30 Ω resistors connected in parallel. What is the total equivalent resistance of this circuit
10 Ω
Is it correct to say that capacitance is inversely proportionally to the area of the parallel plates
False
Resistors connected in series do not share the same current
False
Solid wire is more flexible than stranded wire.
False
Step-up transformers are located near to end user
False
Voltage sources cannot be added in series if they equal values and same polarities
False
When you break a magnet into two, you can separate the two poles
False
The magnetic field strength is weakest at the poles and strongest along the length of the magnet
Galse
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
If the voltage in a electrical circuit containing a lightbulb is increased, what happens to the brightness of the bulb?
Increases
What is an isotope?
Isotopes of an element share the number of protons but have different numbers of neutrons
Naturally occurring magnets in nature are called
Lodestones
How will an open resistor affect a series circuit?
No current will flow in the circuit
Which law is described by the following equation: V or E = I x R?
Ohm's Law
What types of charges repel
Positive and positive
Atomic number is defined as the number of __________ in an atom
Protons
Which of the following statements describes a good solder joint?
Shiny, smooth and a concave fillet
An integrated circuit is made on a _____ piece of Silicon called the chip
Single
A soldering iron or a soldering gun tip is tinned by coating its surfaces with
Solder
Devices used to open and close circuits without the inconvenience of disconnecting and reconnecting wire are called
Switches
Covert 540,000,000 into its corresponding scientific notation
54x10^7
Death caused by an electric shock is called
Electrocution
Wearing safety glasses is very important while soldering
True
Which of these colors is NOT used in the resistor value code
Turquoise
You can tell if an object is magnetic if the groupings of atoms:
are lined up in the same direction
Advantages of digital meters over analog meters are
display, accuracy and no ambiguity
An N-type semiconductor has excess of
electrons
A transistor is used for
Switching voltages & currents and also for amplifying small signals into large currents. (Both the above)
The faster the coil of a generator rotates though the magnetic field the
The higher the output voltage
What happens when you turn off the current in an electromagnetic
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.
What value of resistor would produce a current of 3 A in a circuit when a 12 V battery is connected
4 A
A series circuit contains five resistors. The total resistance for the circuit is 186 Ω. The values of four of the resistors are: 20Ω, 14Ω, 10Ω and 100Ω. What is the value of the fifth resistor?
42 Ω
Which of the following are electrical hazards
All of the above are electrical hazards
The best insulators are;
All of the choices given here
Commonly used transistor
BJT
Identify the semiconductor
Silicon
Soldering is the process of joining metals using another metal that has a ______________melting point.
lower
Direction of electron flow in a circuit is always from
negative to positive
Electron is a
negatively charged particle
The term "milliamp" means __________ of an amp.
1/1000 th
Transistor is a
3-terminal device
Ohmmeter measures
resistance
Current does not flow in a forward biased diode.
False
Diode conducts in both directions
False
In a parallel circuit, if one of the bulbs blew out, the other bulb would not be able to light up
False
Insulators offer very less resistance to the flow of electricity.
False
If 5 V and 16 V power supplies are connected in series-opposing, what is the total voltage?
11 V
Electrical Generator performs which kind of energy conversion?
mechanical energy to electrical energy
Atomic mass is defined as the mass of a/an ________ of an atom
nucleus
A magnet made of a material that keeps its magnetism is known as a:
permanent magnet
If a battery produced 12.6 Volta and what would be the current flow be for a 6 Ohm resistor
2.1 A
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 Watt
How much current flows in a circuit with a 18-volt battery and six 1 ohm resistors (bulbs) in series
3 A
What is the current flowing in a 20 Ω resistor, when the voltage E=120 Volts
6 Amps
A resistor's first three color bands are; White, Green, Red - What is its value
9.5 KΩ
A ferromagnetic material is
A material that shows strong magnetic effects
ferromagnetic material is
A material that shows strong magnetic effects
What are the effects of moving a close wire loop through a magnetic material
All of the choices listed here
Which amongst the following choices listed below is NOT attracted to a magnet
Aluminum
You can tell if an object is magnetic if the grouping of atoms______
Are lined up in the same direction
Why do we use an electroscope
Because we want to know it an object is charged or no
A 65 K Ω resistors would have which colors on its first 3 bands
Blue, Green, Orange
When the plate area of a capacitor increases;
Capacitance increases
What is the unit that is used to describe electric charge
Coloumb
The first goal(a) to accomplish in analyzing a complex series-parallel circuit is to:
Determine the total resistance and the main current first
The basic parts of a circuit are
Energy Source, Conductive path, Switch and Load
What is it that does not affect the amount of current flow induced by magnetism
Environment
Ammeters are always connected in parallel in a circuit for measuring the currents.
False
An atom is not electrically neutral
False
An electromagnet is a permanent magnet
False
Atomic number is defined as the number of neutrons in an atom
False
Electrical soldering is also called as____________ soldering
soft
Devices used to convert solar energy to electricity are called
solar cells
choose the magnetic materials
steel and iron
The areas of a battery that are marked positive (+) and negative (-) are called:
terminals
An object is not magnetized if
the groupings of atoms are scattered
The voltage across any branch of a parallel circuit is
the same as the other parallel elements
Soft solder is an alloy of _________& ___________.
tin and lead
