Study guide
Exam
Electricity
Electric Forces and Charges
Coulomb’s Law
|
F = k |
q1q2 |
|
d2 |
Coulomb’s law constant k =
9,000,000,000 N·m2/C2
Electric Fields
Static Electricity
Induced Charge
Charge (coulombs)
Electrical poles (positive and
negative)
Current (amperes) = Charge / Time
(coulombs / sec)
Voltage (volts) = Energy /
Charge (joules / coulomb)
Power (watts) = Voltage *
Current (joules / sec)
Direct Current and Alternating
Current
Electrical Resistance (Ohms)
Ohm’s Law
Voltage = Current * Resistance
Series and Parallel Circuits
Magnetism
Magnetic Poles (north and
south)
Magnetic Fields
Magnetic Domains
(Ferromagnetic materials)
Electric Currents and Fields
Electromagnets
Moving Charges and Fields
Electromagnetic Induction – Changing
magnetism leads to electric fields
Generators and AC current
Power Production
Electricity sample questions
1.
A short piece of
PVC pipe is placed on a rotator. Another
short piece of PVC pope is brought near the first piece. Both pieces were rubbed with a rabbit fur and
have excess negative charges on their surfaces.
You will find that:
a.
the two pipes will
repel each other
b.
the two pipes will
attract each other
c.
the effect between
the two pipes cannot be determined
d.
the two pipes will
only attract each other after they touch
e.
there is NO force
between the two pipes
2.
A short piece of
PVC pipe is, again, placed on a rotator.
A piece of clear Plexiglas is brought near the PVC pipe. Both pieces were rubbed with a rabbit fur and
have excess charges. The PVC has negative
charges and the Plexiglas has positive charges.
You will find that:
a.
the two pipes will
repel each other
b.
the two pipes will
attract each other
c.
the effect between
the two pipes cannot be determined
d.
the two pipes will
only attract each other after they touch
e.
there is NO force
between the two pipes
3.
A short piece of metal
is placed on a rotator. A piece of PVC
pipe is brought near the metal. The PVC
pipe has been rubbed with a rabbit fur and has excess negative charges on its
surface. You will find that
a.
the two pipes will
repel each other
b.
the two pipes will
attract each other
c.
the two pipes will
not effect each other
d.
the two pipes will
only attract each other after they touch
e.
there is NO force
between the two pipes
4.
Current measures which of the following electrical properties
of a circuit:
a.
the energy, in
joules, carried by each coulomb of charge passing through the circuit
b.
the amount of
charge, in coulombs, passing through the circuit each second
c.
the amount of
power, in watts, being dissipated by the circuit
d.
current does not
measure an electrical property of a circuit
e.
none of the above
5.
Voltage measures which of the following electrical properties
of a circuit:
a.
the energy, in
joules, carried by each coulomb of charge passing through the circuit
b.
the amount of
charge, in coulombs, passing through the circuit each second
c.
the amount of
power, in watts, being dissipated by the circuit
d.
voltage does not
measure an electrical property of a circuit
e.
none of the above
6.
In the analogy
between electric current and the flow of water down a fire hose, pressure in
the fire hose is similar to which of the following electrical measurements:
a.
voltage
b.
amperage
c.
wattage
d.
coulombs
e.
none of the above
7.
In the analogy
between electrical current and the flow of water down a fire hose, the rate of
water flow down the hose, gallons per second, is similar to which of the
following electrical measurements:
a.
voltage
b.
amperage
c.
wattage
d.
coulombs
e.
none of the above
Magnetism
8.
When the north
poles of two magnets are brought together which of the following is observed:
a.
the force between
the magnets will only occur while they are moving
b.
the two magnets
will attract each other
c.
the two magnets
will not generate any forces
d.
the two magnets
will repel each other
e.
none of the above
9.
When the north pole
of one magnet is brought near the south pole of another magnet, which of the
following is observed:
a.
the force between
the magnets will only occur while they are moving
b.
the two magnets
will attract each other
c.
the two magnets
will not generate any forces
d.
the two magnets
will repel each other
e.
none of the above
10.
When the north
pole of a magnet is brought near a piece of non-magnetized iron, which of the
following is observed:
a.
the force between
the magnet and metal will only occur while they are moving
b.
the magnet and
iron will attract each other
c.
the magnet and
iron will not generate any forces
d.
the magnet and
iron will repel each other
e.
none of the above
11.
When the north
pole of a magnet is brought near a piece of aluminum, which of the following is
observed:
a.
the force between
the magnet and aluminum will only occur while they are moving
b.
the magnet and
aluminum will attract each other
c.
the magnet and
aluminum will not generate any forces
d.
the magnet and
aluminum will repel each other
e.
none of the above
12.
An electromagnet
can be fabricated by:
a.
wrapping wire
around a nail and running current through it with a battery
b.
rubbing rabbit fur
on a PVC pipe
c.
heating a sample
of iron to a high temperature
d.
moving a coil of
wire through a magnetic field very quickly
e.
none of the above
Magnetic Induction
13.
Generators create
electric currents by:
a.
heating strands of
copper wire
b.
exposing a sheet
of aluminum to sunlight
c.
rotating coils of
conducting wires in a magnetic field
d.
with batteries
e.
none of the above
14.
Generators create
electric currents that are:
a.
alternating
currents, ac
b.
direct currents,
dc
15.
Batteries generate
electric currents that are:
a.
alternating
currents, ac
b.
direct currents,
dc
16.
The national power
grid transports energy with which of the following:
a.
direct currents
b.
alternating
currents
c.
lasers
d.
high pressure
steam
e.
none of the above
17.
Moving a magnet
out of the center of a wire loop quickly can “induce” or generate:
a.
heat in the wire
b.
electric currents
in the wire
c.
light through the
center of the loop
d.
nothing in the
wire
e.
this is unknown
General Questions
18.
A 100 watt light
bulb and a 50 watt light bulb are observed from the same distance.
a.
the 100 watt bulb
will appear brighter than the 50 watt bulb
b.
the 50 watt bulb
will appear brighter than the 100 light bulb
c.
the bulbs will
appear equally bright
d.
this depends on
the temperature of the bulbs
e.
it is unknown
which bulb is brighter
19.
The unit called a
watt, is which of the following:
a.
a measure of the
total work done by a device or process
b.
a measure of the
power that a device or process can deliver
c.
a measure of the
energy carried by current traveling down a wire
d.
a measure of the
charge carried by current traveling down a wire
e.
none of the above
20.
A young well
conditioned athlete can always deliver or complete
a.
more work than an
old wimpy college professor
b.
more power than an
old wimpy college professor
c.
more current than
an old wimpy college professor
d.
all of the above
e.
none of the above
Atomic Theory
Components of the Atom
Electrons – carry the negative charge and orbit the
nucleus. Electrons are very light, about
one two thousandth of the mass of a
proton or neutron.
Orbitals / shells – allowed atomic
states, or orbits, in which the electrons are found. Electrons cannot be found in any state but rather only in a discrete set of
possible state. This is evidenced by the discrete spectrum emitted by excited atoms
that we observed in class.
Valence Electrons – Loosely bound electrons in the outermost
orbital or shell. The outmost shell of
the atom can have its electrons
removed or added to easily by chemical means or even possibly by rubbing. The valence
electrons are involved in chemical bonding.
Ions – atoms with valence electrons removed or added,
leading to charged atoms.
Protons – constituents of the nucleus, nucleons. These carry the positive charge in the Atom. The number of protons in an atom determines the element of the atom and
its atomic number.
Neutrons – neutral constituents of the nucleus. They have about the same mass as protons but
carry no charge. They can help to stabilize the nucleus.
Atomic Mass – Total sum of protons and neutrons in
the nucleus.
Chemical reactions – bonds can form between atoms to
make molecules. The resultant
substances are called compounds.
Ionic bonds – one atom gives up a valence electron to
another. The resultant ions possess
negative and positive charges and attract each other. This results in a bond holding the two atoms
together.
Covalent bonds – two atoms with similar affinity to
hold electrons, will share valence electrons and, as a result, bond together into molecules.
Nuclear Physics
Nuclear reactions – reactions that
involved the exchange, or change, of nucleons in an atom. Nuclear reactions
tend to involve much higher energies than chemical reactions.
Transmutations – reactions that change an atom from
one element to another. That is, changes the atomic number,
(number of protons), in the nucleus.
Beta rays or particles – formed when the nucleus
emits an electron or positron (antimatter
electron). Beta decays occur when a nucleon changes from a proton to a neutron, or from
a neutron to a proton, and emits a beta
particle and a neutrino.
Alpha rays or particles – formed when the nucleus
emits a packet of two protons and two neutrons
in a tightly
bound packet.
Gamma rays – the emission of very high frequency electromagnetic
radiation when the nucleus of the atom relaxes. This is a method by which an excited nucleus
can give off excess energy.
Nuclear Energy, (fission), and Reactors
Nuclear fission – certain heavy atoms have the
ability to split apart releasing smaller nuclei called daughter products, neutrons, alpha rays, beta
rays, gamma rays, and heat.
Chain reactions – these can form with fissionable
material. Nuclei undergoing fission release
neutrons that can produce further
fission in a growing chain.
Nuclear reactors - what are some of the advantages
and disadvantages of nuclear energy production by use of fission based chain reactions.
Bombs – atomic bombs, thermonuclear bombs. How do these work and what materials are
required to make these? (Thermonuclear bombs use fusion of tritium
and hydrogen to increase the power over that of atomic bombs.)
Breeder reactors – How do breeder reactors work? How are they different from other reactors. Breeders form fissionable material out of un-fissionable
materials inside the reactor, such as forming plutonium out of uranium 238.
Heavy radioactive materials - Uranium 238, uranium
235, uranium 236, Plutonium, Thorium, Radium, Radon,
and others.
Nuclear fusion, the source of solar energy
Nuclear fusion – certain light nuclei can join
together and form heavier nuclei while releasing energy.
What are some of the advantages and disadvantages of
nuclear fusion in energy production.
Fusion materials of interest - Hydrogen, deuterium,
tritium
Atomic Theory sample questions
1.
Atoms
consist of which of the following particles
a.
electrons
orbiting a nucleus of protons and neutrons
b.
neutrons
orbiting a nucleus of electrons and protons
c.
protons
orbiting about a nucleus of electrons and neutrons
d.
electrons
embedded in a positively charged plasma
e.
protons
embedded in a negatively charged plasma
2.
The
atomic number of an atom equals the:
a.
Number
of protons in the atom
b.
Number
of neutrons in the atom
c.
Number
of electrons in the atoms
d.
Total
number of neutrons and protons in the atom
e.
Total
number of protons and electrons in the atom
3.
The
atomic mass of an atom equals the:
a. Number of protons in the atom
b. Number
of neutrons in the atom
c. Number of electrons in the atoms
d. Total number of neutrons and protons in the atom
e. Total number of protons and electrons in the atom
4.
Valence
electrons can be excited by electricity into higher energy states. When these electrons relax they emit
light. This light can be split into its
component colors with a diffraction grating or a prism. It is then best described by which of the
following:
a.
a
continuous spectrum of light that appears as a rainbow
b.
a
discrete set of narrow spectral lines of different colors
c.
this
light cannot be seen after being directed through a diffraction grating or
prism
d.
atoms
do not emit light under any circumstances
e.
the
valence electrons cannot be excited by electricity
5.
When
atoms gain or loose electrons they are called:
a.
isotopes
b.
ions
c.
valence
d.
prototypical
atoms
e.
atoms
never loose electrons
Nuclear Theory
6.
Carbon
12 and Carbon 14 are examples of two different
a.
Chemical
elements
b.
Molecules
c.
Isotopes
d.
Chemical
Reactions
e.
None
of these
f.
7.
Nuclear
fission is a process where:
a.
heavy
nuclei split into smaller parts called daughter products
b.
light
nuclei fuss together to form larger nuclei
c.
a
neutron changes itself into a proton releases an electron and a neutrino
d.
a
nuclei releases an alpha particle
e.
none
of these
8.