Download Unit B—Energy Flow in Technological Systems

Unit B—Energy Flow in Technological Systems
Unit Assessment
Line M ast er
18
Name: _____________________________________
Section B3.0 Quiz
(20 Marks)
1. What is the difference between:
a) an open system and a closed system?
b) work and heat?
2. State the first law of thermodynamics. Use this law to explain why a bouncing ball will never
bounce back up to the original height that it was released from.
3. Under what condition can a machine or device be considered a perpetual motion machine or
device?
4. State the second law of thermodynamics. Use the law to explain why leaving a refrigerator
door open can never cool down a kitchen.
5. What is the difference between a heat engine and a heat pump? Give a technological example
of each.
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Unit B—Energy Flow in Technological Systems
6. Beside each of the steam engines shown below:
a) Name the inventor chiefly responsible for the invention or development of the engine.
b) Describe one change or innovation in the engine that made it an improvement over its
predecessors.
I. The Savery Engine
II. The Newcomen Engine
III. The Watt Engine
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Unit B—Energy Flow in Technological Systems
7. What two scientific discoveries were fundamental in the design of the first steam engines in the
1600s?
8. A light bulb uses 100 J of electrical energy per second and produces 30 J of useful light energy.
a) Calculate the percent efficiency of the light bulb in converting electrical energy into useful
light energy.
b) Explain what happens to the rest of the energy.
9. An electric train is 35.0% efficient at converting electrical energy into useful mechanical
energy. How much electrical energy must be supplied to give the train 95.0 J of useful kinetic
energy?
10. For each of the energy sources listed below, answer the following questions by filling in the
blanks below each source.

Is the energy source renewable or non-renewable?

Is it classified as a solar or non-solar energy source?

Identify a device or technology that uses this energy as its primary energy source.

Describe the primary energy conversion that takes place in the device or technology.
a) nuclear

renewable or non-renewable ____________________________

solar or non-solar ___________________________________

device that uses this technology as its primary energy source
_________________________________

primary energy conversion in this device or technology __________________________
b) fossil fuels

renewable or non-renewable ____________________________

solar or non-solar ___________________________________

device that uses this technology as its primary energy source
_________________________________

primary energy conversion in this device or technology __________________________
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Unit B—Energy Flow in Technological Systems
c) geothermal

renewable or non-renewable ____________________________

solar or non-solar ___________________________________

device that uses this technology as its primary energy source
_________________________________

primary energy conversion in this device or technology __________________________
d) tidal energy

renewable or non-renewable ____________________________

solar or non-solar ___________________________________

device that uses this technology as its primary energy source
_________________________________

primary energy conversion in this device or technology __________________________
e) wind energy

renewable or non-renewable ____________________________

solar or non-solar ___________________________________

device that uses this technology as its primary energy source
_________________________________

primary energy conversion in this device or technology __________________________
f)




biomass
renewable or non-renewable ____________________________
solar or non-solar ___________________________________
device that uses this technology as its primary energy source
_________________________________
primary energy conversion in this device or technology __________________________
11. Identify and discuss two factors that could eventually lead our societies into an energy crisis in
this century.
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Unit B—Energy Flow in Technological Systems
12. Discuss what the term “sustainable” would mean to the following people:
a) an employee of the petroleum industry
b) an environmentalist
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Unit B—Energy Flow in Technological Systems
Answers to Section B3.0 Quiz
1. a) An open system can exchange matter and energy with its surroundings. A closed system
can exchange only energy with its surroundings.
b) Work involves the movement of matter, while heat involves the movement of thermal
energy.
2. The total energy in a system, including heat, remains constant. When the ball hits the floor, all
the kinetic energy is not converted to kinetic energy as the ball moves back up. Some energy is
lost as heat during the collision with the floor.
3. A device or a machine can be considered a perpetual motion device when all the energy
supplied to the device or machine is converted to mechanical energy. No energy is lost to the
surroundings as heat.
4. Heat flows naturally from hot to cold objects, and in the process, it can be made to do work.
The refrigerator is doing work to perform the opposite process. It is transferring cold to hot,
which is not a natural process, so work must be done. In the process of doing work, the fridge
will heat up a room instead of cooling it off.
5. A heat engine, such as a thermoelectric converter, uses heat energy to create mechanical
energy. A heat pump, such as a refrigerator, uses mechanical energy to transfer thermal energy.
6. a) I. Thomas Savery; II. Thomas Newcomen; III. James Watt
b) I. This pump had a separate boiler to produce the steam. It used one-way valves instead of
a reciprocating piston.
II. This engine was easy to build and maintain. Also the action of a piston driving a beam
back and forth to pump water could produce more force to lift water through higher
distances.
III. This engine had a separate container to condense the steam so that the boiler always
remained hot. Both the upward and downward strokes delivered power. Also a flywheel
was attached to convert the back and forth motion of the piston into rotary motion.
7. A vacuum created in a closed cylinder has tremendous forces. Water converted into steam
increases its volume by 1300 times.
8. a) 30%
b) The rest of the energy is lost as heat.
9. 271 J
10. Examples of devices/technologies will vary. Those included in the answers below are just
some possibilities.
a) nuclear: non-renewable; non-solar; electrical generating stations. Nuclear energy is
converted to heat to heat water.
b) fossil fuels: non-renewable; solar; thermal electrical generating stations. Chemical
potential energy from combustion is converted to heat.
c) geothermal: non-renewable; non-solar; used to heat water for heating systems. Nuclear
reactions produce heat.
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Unit B—Energy Flow in Technological Systems
d) tidal: renewable; non-solar; electrical generating stations. Mechanical energy of moving
water is converted to mechanical energy in rotating turbines.
e) wind: renewable; solar; electrical generating stations. Mechanical energy of moving wind
is converted to mechanical energy of rotating turbines.
f) biomass: renewable; solar; electrical generating stations. Combustion converts stored
chemical energy to heat.
11. Increasing population—the population of the world is growing at an exponential rate, placing
greater demands on energy supplies.
Increasing demands—the changing of societies into industrialized societies is increasing the
demand for energy supplies.
12. a) “Sustainable” means to ensure energy for future generation. To an employee of the
petroleum industry, this would mean searching for enough reserves to ensure supplies for
future generation.
b) “Sustainable” means to ensure a quality environment for future generations. To an
environmentalist, this would mean developing energy sources that do not pollute or damage
the environment.
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