Aircraft Electricity 1
What device is designed to open and disconnect a circuit in the event of excessive current?
fuse
Direct current is decreased as ___________.
Uni-directional
The amount of potential necessary to cause one coulomb to produce one joule of work is a(n) __________.
Volt
What force pushes the electrons through a resistance in a circuit?
Voltage
What is another term for electromotive force (EMF)?
Voltage - Pressure
Resistors functioning as _________________ are used in applications involving field-effect transistors (FETs) and multi-range voltmeter circuits.
Voltage dividers
What unit is used to express electrical power?
Watt
The amount of electrical power being used in a circuit is measured in __________.
Watts
If a circuit is open, current ___________________ flow.
Will not
A voltage that is positive with respect to ground is a(n) ____________________________________ voltage.
above ground
In parallel circuits, the voltage drop across any branch is the same as the _________________.
applied voltage
A basic law of magnetism states that unlike poles ___________ and like poles _____________.
attract, repel
If a permanent magnet is cut into pieces, each piece __________ a separate magnet.
becomes
Altering current is described as ___________.
bi-directional
A combination circuit is a circuit that contains ____________________.
both series and parallel components.
A complete circuit is often referred to as a(n) _______________ circuit.
closed
The angular difference between true north and magnetic north is known as the angle of ______________.
declination
Magnetism can be explained in terms of _______________ spin patterns.
electron
Insulators are the only materials that can hold __________ stationary
electrons.
In the English system of measure, magnetic strength is measured in terms of _____________________.
flux density.
Magnetic lines of force are referred to as ________________.
flux lines
The neutral conductor is also referred to as the ________ conductor.
grounded
A series circuit _________________ path(s) for current flow.
has one
Electrostatic charges occur on _____________.
insulators
To locate the north pole of an electromagnet, use the ________ -hand rule.
left
Man-made permanent magnets retain their magnetism _____ than natural magnets.
longer
Lodestone is a name for a naturally occurring magnetic material that is also called ________________.
magnetite
What type of fixed resistor is made by applying a film of metal to a ceramic rod in a vacuum?
metal film
What type of fixed resistor is made by combining metal with glass and then applying it to a ceramic base as a thick film?
metal glaze
What type of resistor operates by moving the wiper arm with a screw of some number of turns?
multi-turn variable resistor
If a thundercloud has a positive charge, the current in the lightning bolt will flow from the ____________________.
negative
Within a lightning bolt, current flows _____________________________________.
negative to positive.
A junction point of current paths is often called a _____________.
node
The shock that results from walking across a carpet and touching a doorknob is an example of a(n) _________________ static charge.
nuisance
The current, voltage, power, and resistance in a series circuit can be calculated using ______________ law.
ohms
Circuits that have more than one path for current flow are _____ circuits.
parallel
By observing the direction of current flow through the circuit, voltage ____________________ can be determined.
polarity
What is another term for a variable resistor?
potentiometer
Solving combination circuits includes a step in which you ___________________________________________________________________.
reduce the circuit to a simple circuit.
A variable resistor with two terminals is called a ______________.
rheostat
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
There is very little resistance and a large amount of current flows in a(n) _________________ circuit.
short
In a parallel circuit, the total current flow is equal to the _________ of the currents through all the branches.
sum
The static charge sometimes used during spray painting is called a _____ static charge.
useful
A resistor whose values can be varied over a range of values is called a ______________ resistor.
variable
Which is correct concerning a parallel circuit?
Total resistance will be smaller than the smallest resistor.
What type of fixed resistor is made by applying a film of carbon to a ceramic rod?
carbon film
A point that is used as a common connection for other parts of a circuit not actually driven into the ground is called a _____________ ground.
chassis
The regions formed in the molecular structure of magnetic metals are sometimes called magnetic _____________.
domains
In the English system, the total force producing a magnetic field is the _______________________.
magnetomotive force
In a clothes dryer, the greatest static charges generally are built up on ________________ fabrics.
man-made
When an object protected by a lightning ___________ is struck by a lightning bolt, it will bleed the lightning discharge to ground before the protected object can be harmed.
rod
Selenium is a(n) ________________.
semi-conductor
A circuit that has only one path for current flow is a ______________ circuit
series
Combination circuits are circuits that contain both series and parallel branches.
true
The values of a resistor can often be determined by the "color code."
true
A conductor is made from a material that contains between _________ valence electrons.
1 and 3
An electrical circuit has a voltage of 50V and a resistance of 5Ω. What is the value of current?
10A (I=E/R)
An electric circuit has a resistance of 20Ω. The current is measured to be 6A. How many volts are applied to the circuit?
120V (E=I*R)
A toaster is listed as 1560 W. When it is plugged into a 120V circuit and starts to make toast, how many amperes will it draw?
13A (I=P/E)
A three-branch parallel circuit has a total resistance of 385.83Ω. Two of the resistors are 680Ω and 1500Ω. What is the value of the third resistor?
2200Ω
A 24V source is required to furnish 48W to a parallel circuit consisting of four resistors of equal value. What is the voltage drop across each resistor.
24V - stays the same
The Greeks were the first to discover electricity about _________ years ago.
2500
A parallel circuit is composed of two 60Ω resistors. What is the total resistance?
30Ω (Rt=1/((1/R1)+(1/R2)))
A semiconductor contains ________ valence electrons.
4
Approximately how many horsepower is an electrical device listed as 3000 watts?
4.02HP (745.7w to 1hp)
An electrical motor is running on 120V. The current is measured to be 2A. How many Ohm's of resistance is the motor?
60Ω (R=E/I)
A parallel circuit composed of a 10Ω and a 22Ω resistor has a voltage of 60V. What is the current in the 10Ω resistor?
6A (I=E/R)
What is the maximum number of valence electrons in an atom?
8
A three-branch parallel circuit has resistors of 27Ω, 56Ω, and 15Ω. What is the total resistance?
8.23Ω (Rt=1/((1/R1)+(1/R2)))
What is the applied voltage in a series circuit with two resistors (25V and 60V, respectively)?
85V (Voltage applied to a series circuit is equal to the sum of the individual voltage drops.)
A method for finding total resistance of parallel resistors is ___________.
A. product / sum B. reciprocal formula C. resistors of equal value D. All of the above D
What type of current reverses its direction of flow at regular intervals?
AC - Alternating current
A precipitator is a type of ____________________.
Air Filter
One coulomb per second is equal to one _________.
Ampere.
What force is demonstrated in objects with unlike charges?
Attraction
What type of current flows in only one direction?
DC - Direct Current
To symbolize a ground point made by physically driving an object such as a rod or pipe into the ground, a(n) _________________ ground symbol is used.
Earth
What type of magnet depends on flowing current to produce a magnetic field?
Electromagnet
Electrical current is the flow of ___________.
Electrons
Which of the following formulas is the general voltage divider formula?
Ex= (Rx/Rt)*Et
A thundercloud contains only positive electric charges.
False
Current always flows from positive to negative.
False
During normal operation of a typical 120-volt appliance circuit, current flows through the hot, grounding, and neutral conductors.
False
In electrical schematics, the symbol used to represent a resistor is standard.
False
Voltage flows through an electric circuit like water flows through a pipe.
False
What type of resistors can only have ohmic value?
Fixed
What standard prefic in engineering notation indicates multiplication by 1,000,000,000?
Giga
What color used as the multiplier band means to divide the combined first two numbers by 10?
Gold
Static electricity refers to electrons that ________________moving.
Are not
What type of fixed resistor is made from a compound of carbon graphite and resin bonding material?
Composition carbon
What part of an atom has a negative charge?
Electron
The three substances that form natural magnets are ______,________, and ______.
Iron, nickel, cobalt
What is the most common method of producing electricity?
Magnatism
The precipitator uses a high-voltage DC power supply to provide a set of wires with a positive charge and a set of plates with a ________ charge.
Negative
The unit of resistance to current flow is the _________.
Ohm
The statement, "In a DC circuit, the current is directly proportional to the voltage and inversely proportional to resistance," is known as _________ law.
Ohm's
The valence shell of an atom is the ________ shell.
Outer
What part of an atom has a positive charge?
Proton
What are the three principle parts of an atom?
Proton, neutron, electron
The atomic number of an element is the number of ____________ in the nucleus.
Protons
The nucleus of an atom contains ____________________.
Protons and Neutrons
A basic law of physics states that like charges _______ and opposite charges _______.
Repel, Attract
What force is demonstrated in objects with like charges?
Repulsion
What causes a wire to become warm when current flows through it?
Resistance
The semi-conductor material used as a coating on copy machine drums is ______________.
Selenium
What part of an atom has no charge?
Neutron
An electroscope can be used to determine the polarity of an electrostatic charge.
True
Copy machines operate on the principle of static electricity.
True
Lightning is the result of static charge built up in the clouds that contain a large amount of moisture.
True
Lightning rods provide an easy path to ground for current.
True
The velocity of AC through a conductor is ____________ the speed of light.
less than
The measure of a material's ability to be magnetized is called _______________.
permeability
A parallel circuit composed of a 150Ω and a 270Ω resistor has a voltage of 120V. What is the current in the 150Ω resistor?
.8A (I=E/R)
A series circuit has a total resistance of 180Ω and an applied voltage of 120V. What is the current flow?
.667A (I=E/R)
A three-resistor circuit has a total power of 25W. Two of the resistors dissipate 10W and 5W, respectively. How much power does the third resistor dissipate?
10W
A two-branch parallel has a 30Ω and a 15Ω resistor. What is the total resistance?
10Ω (Rt=1/((1/R1)+(1/R2)))
A two-resistor series circuit has an applied voltage of 100V. The voltage across one of the resistors is 40V. What is the voltage across the other resistor?
60V (Voltage applied to a series circuit is equal to the sum of the individual voltage drops.)
An insulator is a material containing ____________ valence electrons.
7 and 8
A series circuit has a total resistance of 240Ω and a current flow of 4A. What is the applied voltage?
960V (E=I*R)
What is the smallest part of an element that still retains the properties of that element?
Atom
Imagine a water system with a holding tank, pump, and return lines. What would happen to the resistance to flow if a return path is added to the system.
Lessens
The north magnetic pole of a compass needle is attracted to the ________________ magnetic pole of the earth.
South
An increase in ___________, not resistance, results in an increase of load.
current
In series circuits, the _____________ is the same at any point in the circuit.
current
The term: "load" refers to the amount of ____________ in a circuit branch.
current
When a circuit has only one path, the ______________ is the same at any point.
current
Parallel circuits are also referred to as ______________.
current dividers
A voltage ________ is used to provide different voltages between certain points in a circuit.
divider
In a series circuit, the sum of the voltage drop is ______________ the applied voltage.
equal
One of the rules for parallel circuits states that the voltage is different across each branch of the circuit.
false.
In a parallel circuit, the total resistance is _______________________________ value resistor.
less than the
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 variable resistor with three terminals is called a ______________.
potentiometer
The ______________ of a resistor indicates the plus and minus limits of a resistors ohmic value.
tolerance
What is indicated by the fourth color band on a resistor?
tolerance
In a combination circuit, to identify series and parallel elements, you should ________________________.
trace the current path.
The 3 rules for parallel circuits are as follows: 1. The voltage drop across any branch of a parallel circuit is the same as the applied voltage. 2. The total current is the sum of the individual currents through each path in the circuit(current adds) 3. The total resistance is the reciprocal of the sum of the reciprocals of the branch resistances.
true
The 3 rules for series circuits are as follows: 1. The current is the same at any point in the circuit. 2. The total resistance is the sum of the individual resistances. 3. The applied voltage is equal to the sum of the voltage drops across all resistors.
true
Earth contains magnetic poles.
True
The grounding prong of a plug should never be cut off or bypassed.
True
Matter can exist in only two states: solid or liquid.
False
Most lightning discharges associated with a cloud occur between the cloud and the ground.
False
The north pole of a compass needle points in the direction of the south geographic pole.
False
There are many more resistance values available for ten percent tolerance resistors than for one percent tolerance resistors.
False
A grounding conductor helps prevent a shock hazard in the event that an ungrounded, or hot, conductor comes in contact with the case or frame of an appliance.
True
The strength of an electromagnet is primarily proportional to its ___________________________.
ampere turns
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 ____________.
arrester
The measure of a materials resistance in magnetism is known as ____________________.
reluctance.
A series circuit has two resistors that dissipate 10W and 15W, respectively. What is the total power dissipation of the circuit?
25W
How many color bands are used on resistors that have a tolerance of +-20%?
3
What type of circuit generally occurs when the conductors leading from and back to the power source become connected?
Short circuit
Matter has mass and occupies space
True
What law states that the force of electrostatic attraction or repulsion is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them?
Coulombs law
If an object is placed in the field of a strong electromagnet connected to an AC line, the object will be _________________________.
De-magnetized
What type of magnets do not require any power of force to maintain their field?
Permanent
The amount of current flowing through each resistor is directly proportional to its resistance.
true
When solving combination circuits, it is generally easier if the circuit is reduced to simpler circuits.
true
The amount of ___ across a resistor is proportional to its resistance.
voltage drop
What type of fixed resistor is made by winding a piece of resistive wire around a ceramic core?
wire wound
What type of resistors are generally used when a high power rating is needed?
wire wound
