Physics 1070 Second
Hourly Exam November 24, 1999
This is a closed book exam. Be
careful not to share your answers with anyone else, since the
hallmark of science is honesty and integrity. Write all your
answers carefully, completely, concisely, and legibly in the spaces
provided on these exam sheets. Anything that can't be easily
read and understood by the grader will be marked wrong. The
100 points for this exam will be worth 15% of your final grade.
1. True or False: Mark
the following statement either true (T) or false (F) on the basis
of the reading and discussions of this class. (30 points, 3 for
each correct item).
increases the proportion of fertile nuclei in uranium over that
normally found in nature. Enrichment increases the fraction
of "fissile" nuclei.
b) During the last century,
the carbon dioxide concentration in the earth's atmosphere has
c) In a "linear
dose theory" it is assumed that there is a minimum radiation
dose below which no biological damage is done. In the linear
theory, damage is proportional to dose all the way down to zero
d) The Chernobyl incident
put more radioactive material into the earth's atmosphere than
all nuclear weapons tests combined.
e) Hydroelectric power,
like nuclear power, is independent of the current energy from
the sun. Water power gets its ulimate power from the sun.
f) The wavelength of
microwave radiation is less than that of ultraviolet since its
energy is less. MW energy is less but its wavelenth greater
g) Nuclear fission energy
is dependent upon the fact that more fission neutrons are released
than are absorbed, which is not necessary for nuclear fusion energy.
h) The strong nuclear
attractive force has a significant effect on the atomic electrons.The
strong nuclear force is very short-ranged and doesn't extend out
to the atomic electrons.
i) The albedo of the
earth would decrease if all of the polar ice caps melted.
With less ice, there would be less overall reflectivity.
j) Volcanic eruptions
tend to lower temperatures of the earth's surface.The dust
reflects solar energy, keeping it away from the earth.
2. Multiple choice: Pick
the numbered item which best completes the statement (20 points,
4 for each correct item).
a) Coal power is less
"environmentally friendly" than natural gas because?
1. There is less of it.
2. There is more of it.
3. It contains a greater percentage of carbon.
4. It contains a smaller percentage of carbon.
5. It burns at a higher temperature.
6. It requires cooling towers.
b) The cost of mining
has gone up in recent times because?
1. Miner's wages have increased.
2. The cost of mining machinery has gone up.
3. Governments have discouraged mineral exploration.
4. The demand for metals has decreased.
5. More ore has to be dug to obtain the same amount of desired material.
6. Taxes on minerals have
c) M.K. Hubbert argues
that the production history (amount produced) of an energy commodity
such as oil is best described by a?
1. Logistic curve
2. Normal curve
3. Quadratic curve
4. Exponentially rising curve
5. Exponentially falling curve
6. Straight line
d) If the load factor
of a given form of transportation doubles, the per capita energy
cost of transportation by this method.
1. Is doubled
2. Is halved
3. Remains the same
4. Is quadrupled
5. Is cut in quarter
3. Matching: Choose
the item in the column on the right that, on the basis of course
readings and discussions most closely associates with the
description on the left. (30 points; 3 for each correct matching)
[Bonus: extra 5 points; define, in one or two sentences,
any one of the items listed in the right hand column.]
|17||a) Radiation exposure x quality factor||1) moderator|
|20||b) The result of solar energy of the distant past||2) fissile nuclei|
|10||c) The conversion of visible light from the sun into trapped infared radiation||3) microwave radiation
4) control rod
|14||d) Electromagnetic energy of very high frequency||5) plate tectonics|
|16||e) The Rasmussen report||6) Hubbert method|
|18||f) High fossil fuel input farming||7) troposphere|
|9||g) The solar electromagnetic frequencies, which are least absorbed by the earth's atmosphere||8) stratosphere
9) atmospheric window
|13||h) The nucleus of the common helium atom||10) greenhouse effect|
|1||i) Slows neutrons to enhance energy production by nuclear fission||11) albedo
|8||j) The stable part of the earth's atmosphere||13) alpha particle
14) gamma radiation
15) nuclear fusion
16) event tree
18) North American agriculture
19) swidden agriculture
20) fossil fuel
Extra credit definition:
4. Short essays: Answer
any two of the following questions (20 points, 10 for each correct
essay). In your answers, do not rely solely on your own
opinions. Back them up with information obtained from the text
and class discussions. (Bonus 10 points for complete answer to
a third question.)
a) Defend or criticize the following
statement: The world should emphasize nuclear power instead of
relying upon fossil fuels. Both pose severe threats to our
lives and our environment; we have a limeted amount of fossil
fuels which will run out in the forseeable future whereas nuclear
energy could take us thousands of years into the future.
b) Is it true that the best plan
for the future of the world's agriculture is to concentrate on
the fewest possible varieties of the most energy efficient plants?
Explain your answer. Not a good plan since it would lead
to a very unstable agricultural system - one plant disease or
pest could then deprive most of humanity of its food supplies.
c) Explain the following statement:
If it can be achieved, nuclear fusion power is a better answer
to the world's energy needs than is nuclear fission power. Fusion
power does not produce the large amount of radioactive waste that
is charachteristic of fission power and there is potentially more
of it available.
d) Explain the similarities and
differences between "wind power" and hydroelectric power".
Show how both are ultimately forms of "solar power".
Both depend upon the sun; the wind arises from differently
heated parts of the earth's surface due to the different solar
intensity at different latitudes whereas water power depends upon
different levels of the earth's surface, the sun evaporating water
at sea-level (low) , dumping it as rain over the hills and mountains
(high) from which it runs down, converting its gravitational potential
energy into kinetic energy of moving rivers.
e) How is it possible to use
the amount of oxygen found in the earth's atmosphere and crust
to estimate the total amount of fossil fuel available? Criticize
this estimate. If all of the atmospheric and crustal oxygen
is a result of past photosynthesis, as is all of the fossil fuels,
then there is a unique relation between the amounts of each, set
by the well-understood chemistry. Measuring the amount of one
tells you how much exists of the other. But suppose we can't
measure all of the oxygen accurately - it may be buried deep underground
or under the seas. Or, suppose that some of the fossil fuels
are not the product of terrestial photosynthesis, e.g., were deposited
in the earth at its creation.
f) Explain why urban areas are,
or are not, warmer and have more pollutants, than their surrounding
rural areas. Does the city environment influence that of local
and distant rural areas? Dry city concrete has a lower heat
capacity than moist soil and vegetation, hence rises to a higher
temperature for a given amount of received solar energy; some
of the solar energy falling on vegetation is turned into stored
chemical energy via photosynthesis whereas all falling on concrete
becomes heat meaning increased temperature; also, the tall urban
buildings block cooling breezes. The concentration of people,
vehicles, industry, and buildings, characteristic of urban areas,
produces both more heat energy and mor pollutants than do rural
areas. But pollution and heat don't stay still - they can be,
and are, transported from the city to close and distant rural
areas by wind an wqter flows.
g) Defend or criticize the statement:
The mandatory introduction of catalytic converters for American
automobiles was desirable for the efficiency of our transportation
system and the well being of our environment. When initially
introduced, catalytic onverters reduced the number of miles per
gallon achievable by cars and trucks, e.g., the efficiency, even
though it cut dopwn on some of the gaseous pollutants. The fuel
had to be reformulated to protect the catalysts which reliminated
other , metallic, pollutants. Later on, reductions in car weight
and the introduction of computer monitored and controlled engines
restored, and even improved upon, the previous transportation