Unit 1 atomic structure
an electrical circuit has a voltage of 50 v and a resistance of 5 ohms. What is the value of current?
10 A
an electric circuit has a resistance of 20 ohms. the current is measured to be 6 a. How many volts are applied to the circuit?
120
A toaster is listed as 1560 W. When it is plugged into a 120 V circuit and starts to make toast, how many amperes will it draw?
13
approximately how many horsepower is an electrical device listed as 3,000 watts
4
An electric motor is running on 120 v. The current is measured to be 2 A. How many ohms of resistance is the motor
60
What type of current reverses it's direction of flow at regular intervals?
Alternating
What type of current is flows in only one direction?
Direct
Matter can only exist in only two states: solid or liquid
False
unit of resistance to current flow is the ____
Ohm
Matter has mass and occupies space
always true
one coulomb per second is equal to one
ampere
What is the smallest part of an element that still retains the properties of that element?
an atom
Alternating current is described as ____.
bidirectional
The theory stating that current flow is produced when an electron from one atom knocks electrons of another atom out of orbit is generally called the _____ theory
bump
a complete circuit is often referred to as a _____ circuit
closed
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
What is the maximum number of valance electrons in an atom
eight
What part of an atom has a negative charge?
electron
the theory concerning current flow that is most widely accepted as being correct is the ____ flow theory
electron
What are the three principle parts of an atom
electron, proton, neutron
Electrical current is the flow of _____
electrons
what did william gilbert call material that could be charged
elektriks
Voltage flows through an electric circuit like water flows through a pipe.
false
during normal operation of a typical 120-volts appliance circuit, current flows through the hot, grounding, and neutral conductors
false
the greater the difference in the number of electrons between the negative and positive terminals, the greater the what?
force of repulsion and attraction
a semi-conductor contains ____ valance electrons
four
what standard prefix in engineering notation indicates multiplication by 1,000,000,000
giga
any object repelled by a piece of what rubbed on silk would have a positive charge
glass
The neutral conductor is also referred to as the _____ conductor.
grounded
what contains seven or eight valance electrons
insulator
in bump theory what happens to the striking electrons energy
it gives its energy to the electron being struck
if an atom containing two valance electrons is struck by a moving electron, what happens to the energy of the striking electron
it is divided between the two valance electrons
the velocity of AC through a conductor is _____ the speed of light
less than
what is the most common method of producing electricity
magnetism
The smallest part of a compound that still has the properties of that compound is a
molecule
conventional current flow theory states that current flows from the most positive point to the most
negative point
the nucleus of an atom contains
neutrons and protons
The statement "in a DC circuit, the current is directly proportional to voltage and inversely proportional to resistance" is known as ________ law
ohms
a conductor is made from a material that contains between ______ valance electrons
one and three
the valance shell of an atom is the _____ shell
outer
producing electricity from light involves the use of particles called
photons
What part of an atom has a positive charge?
proton
the atomic number of an element is the number of _____ in the nucleus
proton
the 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
an insulator is a material containing _____ valance electrons
seven or eight
What type of circuit generally occurs when the conductors leading from and back to the power source become connected
short
which of the following is one of the two most common materials used in the production of electronic components
silicon
The grounding prong of a plug should never be cut off or bypassed.
true
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 amount of potential necessary to cause one coulomb to produce one joule of work is a
volt
what is another term for electromotive force (EMF)
voltage
the amount of electrical power being used in a circuit is measured in ____
watts
If a circuit is open, current _____ flow.
will not
