Physics - Thermodynamics 2 - Laws of thermodynamics
Note: My reference book is physics book which first law of thermodynamics formula is
“change in U = QW” representing the work done on the system dealing with behavior of
the gas as thermal physics while other physics, thermodynamics and engineering books
presented the first law of thermodynamics formula as “change in U = Q - W”
representing work done by the system dealing with work on its environment which can
be used to form other types of energy such as mechanical, or electrical energy. Both
formulas of the first law of thermodynamics are the same. In my reference Physics
book, the equivalent formula of engineering is “change in U = Q - Wenv “.
Multiple choice; Select the best answer.
1. The internal energy of a system can be increased either by adding energy to the
system or by doing work on it.
a. first law of thermodynamics c. third law of thermodynamics
b. second law of thermodynamics d. fourth law of thermodynamics
2. When a gas expands inside the cylinder, it does work outside its surroundings.
a. work done by the cylinder c. work done on the cylinder
b. work done by the gas d. work done on the gas
3. The work(W) done on a gas (internal energy) at constant pressure(P) is given by
formula W = -P x change in V, where V is volume. Which of the following statements
is/are correct?
a. If the gas is compressed, change in Volume is negative and Work is positive.
b. If the gas is expanded, change in Volume is positive and Work is negative.
c. The work done by the gas on its environment is simply the negative of the work done
on the gas.
d. all of the above
4. In formula W = -P x change in V, what will happen if there is no change in volume?
a. Work decreases. c. Work is constant.
b. Work increases. d. Work is zero.
5. The gas in the cylinder is at a pressure equal to 1.01 x 105 Pa and the piston has an
area of 0.100 m2. As energy is slowly added to the gas by heat, the piston is pushed up
a distance of 4.00 cm. Calculate the work done by the expanding gas on the
surroundings, Wenv, assuming the pressure remains constant.
, a. 400 J c. 408 J
b. 404 J d. 412 J
6. A gas in a cylinder moves a piston with area 0.200 m 2 as energy is slowly added to
the system. If 2.00 x 103 J of work is done on the environment and the pressure of the
gas in the cylinder remains constant at 1.01 x 105 Pa, find the displacement of the
piston.
a. 9.60 x 102 m c. 9.80 x 102 m
b. 9.70 x 102 m d. 9.90 x 102 m
7. The change in internal energy(U) of a system is equal to the heat that flows into the
system(Q) minus the work(Wenv) done by the system on its surroundings.
change in U = Q - Wenv
a. first law of thermodynamics c. third law of thermodynamics
b. second law of thermodynamics d. fourth law of thermodynamics
8. What will happen to the change in internal energy if the system goes through a cyclic
process in which all the thermodynamic variables—pressure, volume, temperature, and
moles of gas—return to their original values.
a. The change in internal energy will be zero
b. The change in internal energy will be constant
c. The change in internal energy will decrease
d. The change in internal energy will increase
9. Suppose the internal energy of an ideal gas rises by 3.00 x 103 J at a constant
pressure of 1.00 x 105 Pa, while the system gains 4.20 x 103 J of energy by heat. Find
the change in volume of the system.
a. 1.10 x 10-2 m3 c. 1.30 x 10-2 m3
b. 1.20 x 10-2 m3 d. 1.40 x 10-2 m3
10. A thermal process in which the pressure of the gas remains constant during the
expansion or compression.
a. adiabatic Process c. isothermal Process
b. isobaric process d. isovolumetric Process
11. A thermal process in which no energy enters or leaves the system by heat, such a
system is thermally isolated from its environment.
a. adiabatic Process c. isothermal Process
b. isobaric process d. isovolumetric Process
Note: My reference book is physics book which first law of thermodynamics formula is
“change in U = QW” representing the work done on the system dealing with behavior of
the gas as thermal physics while other physics, thermodynamics and engineering books
presented the first law of thermodynamics formula as “change in U = Q - W”
representing work done by the system dealing with work on its environment which can
be used to form other types of energy such as mechanical, or electrical energy. Both
formulas of the first law of thermodynamics are the same. In my reference Physics
book, the equivalent formula of engineering is “change in U = Q - Wenv “.
Multiple choice; Select the best answer.
1. The internal energy of a system can be increased either by adding energy to the
system or by doing work on it.
a. first law of thermodynamics c. third law of thermodynamics
b. second law of thermodynamics d. fourth law of thermodynamics
2. When a gas expands inside the cylinder, it does work outside its surroundings.
a. work done by the cylinder c. work done on the cylinder
b. work done by the gas d. work done on the gas
3. The work(W) done on a gas (internal energy) at constant pressure(P) is given by
formula W = -P x change in V, where V is volume. Which of the following statements
is/are correct?
a. If the gas is compressed, change in Volume is negative and Work is positive.
b. If the gas is expanded, change in Volume is positive and Work is negative.
c. The work done by the gas on its environment is simply the negative of the work done
on the gas.
d. all of the above
4. In formula W = -P x change in V, what will happen if there is no change in volume?
a. Work decreases. c. Work is constant.
b. Work increases. d. Work is zero.
5. The gas in the cylinder is at a pressure equal to 1.01 x 105 Pa and the piston has an
area of 0.100 m2. As energy is slowly added to the gas by heat, the piston is pushed up
a distance of 4.00 cm. Calculate the work done by the expanding gas on the
surroundings, Wenv, assuming the pressure remains constant.
, a. 400 J c. 408 J
b. 404 J d. 412 J
6. A gas in a cylinder moves a piston with area 0.200 m 2 as energy is slowly added to
the system. If 2.00 x 103 J of work is done on the environment and the pressure of the
gas in the cylinder remains constant at 1.01 x 105 Pa, find the displacement of the
piston.
a. 9.60 x 102 m c. 9.80 x 102 m
b. 9.70 x 102 m d. 9.90 x 102 m
7. The change in internal energy(U) of a system is equal to the heat that flows into the
system(Q) minus the work(Wenv) done by the system on its surroundings.
change in U = Q - Wenv
a. first law of thermodynamics c. third law of thermodynamics
b. second law of thermodynamics d. fourth law of thermodynamics
8. What will happen to the change in internal energy if the system goes through a cyclic
process in which all the thermodynamic variables—pressure, volume, temperature, and
moles of gas—return to their original values.
a. The change in internal energy will be zero
b. The change in internal energy will be constant
c. The change in internal energy will decrease
d. The change in internal energy will increase
9. Suppose the internal energy of an ideal gas rises by 3.00 x 103 J at a constant
pressure of 1.00 x 105 Pa, while the system gains 4.20 x 103 J of energy by heat. Find
the change in volume of the system.
a. 1.10 x 10-2 m3 c. 1.30 x 10-2 m3
b. 1.20 x 10-2 m3 d. 1.40 x 10-2 m3
10. A thermal process in which the pressure of the gas remains constant during the
expansion or compression.
a. adiabatic Process c. isothermal Process
b. isobaric process d. isovolumetric Process
11. A thermal process in which no energy enters or leaves the system by heat, such a
system is thermally isolated from its environment.
a. adiabatic Process c. isothermal Process
b. isobaric process d. isovolumetric Process
