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Study Guide III Readings: Chapter 11 – The Atomic Nature of Matter Chapter 19 – Vibrations and Waves Chapter 20 – Sound Chapter 21 – Musical Sounds Chapter 22 – Electrostatics Chapter 23 – Electric Current Electricity Electric Forces and Charges
Coulomb’s Law Coulomb’s law constant k = 9.0 X 109 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 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. 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 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 2.
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 3.
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 4.
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 5.
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 6.
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 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 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
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