4TH CLASS ABSA EXAM EXAM STUDY GUIDE
2026 PRACTICE QUESTIONS WITH FULL
SOLUTION GRADED A+
◉ First law of thermodynamics Answer: Energy can be transferred
and transformed, but it cannot be created or destroyed.
◉ Non-Flow Process Answer: A thermodynamic process in which a
working fluid performs work, or has work performed on it, only
within the system boundary.
Heat supplied = Increase in internal energy + Work done
Q = ΔU + W
◉ Steady-flow process Answer: A thermodynamic process whereby
the working fluid enters and exits the system boundaries at she
same constant rate.
Q = U + pv
◉ Enthalpy Answer: The heat content of a system at constant
pressure
,◉ In a certain process, 500 J of work is performed, which gives off
200J of heat. What is the change in internal energy from the process?
Answer: 300 J
◉ In a certain process, 600 J of heat is absorbed by a system, 490 J of
work is done on the system. What is the change in internal energy
for the process? Answer: 1090 J
◉ Second Law of Thermodynamics Answer: Unaided, heat will flow
only from a hot substance to a colder substance.
Heat can be moved from a cold substance to a hot substance.
However, external work must be performed. In a refrigeration
system, this work is performed by the electric motor driving a
compressor. This is NOT a violation of the second law.
◉ liquid-in-glass thermometer Answer: A device for measuring
temperature that consists of a tube with a liquid-filled bulb at one
end. The expansion or contraction of the fluid indicates temperature.
◉ Bimetal thermometer Answer: Two dissimilar metals are rigidly
fixed together and will bend with temp. change due to their different
coefficients of linear expansion
,◉ Pyrometers Answer: Instruments that measure temperatures at
the surface of an object. Typically used for ranges above that suitable
for other kinds of thermometers.
◉ Thermoelectric Pyrometer Answer: Uses a thermocouple to
produce an electric voltage which is proportional to temperature.
◉ Infrared thermometer Answer: A digital device capable of
measuring the temperature of an object at a distance by detecting its
infrared energy emissions.
◉ Specific Heat Answer: The amount of energy required to raise the
temperature of 1 gram of a substance by 1 degree celcius
◉ sensible heat Answer: The heat energy that causes a change in
temperature of a substance but does not contribute to a change in
state
◉ latent heat Answer: heat absorbed or radiated during a change of
phase at a constant temperature and pressure
◉ The specific heat of iron is 0.544 kJ/kg°C. How much heat is given
off if the temperature of a 1.5kg block drops from 80°C to 25°C?
Answer: 44.88kJ
, ◉ coefficient of linear expansion Answer: The change in length per
unit, per degree rise in temperature.
◉ A large diameter steel steam pipe is erected at 20°C and will carry
steam at a
temperature of 320°C. At operating temperatures, how much linear
expansion
will there be in a 30 m long straight section of this steam line?
Answer: 0.108 m
◉ Conduction Answer: Conduction involves the transfer of heat
energy in two ways:
1. From molecule to molecule within an individual substance.
2. From the molecules of one body to those of another body in direct
contact with the first body.
◉ Convection Answer: The transfer of heat by the movement of a
fluid.
◉ Convection Current Answer: The movement of a fluid, due to the
action of gravity on a fluid varying in density, and caused by the
application of heat.
2026 PRACTICE QUESTIONS WITH FULL
SOLUTION GRADED A+
◉ First law of thermodynamics Answer: Energy can be transferred
and transformed, but it cannot be created or destroyed.
◉ Non-Flow Process Answer: A thermodynamic process in which a
working fluid performs work, or has work performed on it, only
within the system boundary.
Heat supplied = Increase in internal energy + Work done
Q = ΔU + W
◉ Steady-flow process Answer: A thermodynamic process whereby
the working fluid enters and exits the system boundaries at she
same constant rate.
Q = U + pv
◉ Enthalpy Answer: The heat content of a system at constant
pressure
,◉ In a certain process, 500 J of work is performed, which gives off
200J of heat. What is the change in internal energy from the process?
Answer: 300 J
◉ In a certain process, 600 J of heat is absorbed by a system, 490 J of
work is done on the system. What is the change in internal energy
for the process? Answer: 1090 J
◉ Second Law of Thermodynamics Answer: Unaided, heat will flow
only from a hot substance to a colder substance.
Heat can be moved from a cold substance to a hot substance.
However, external work must be performed. In a refrigeration
system, this work is performed by the electric motor driving a
compressor. This is NOT a violation of the second law.
◉ liquid-in-glass thermometer Answer: A device for measuring
temperature that consists of a tube with a liquid-filled bulb at one
end. The expansion or contraction of the fluid indicates temperature.
◉ Bimetal thermometer Answer: Two dissimilar metals are rigidly
fixed together and will bend with temp. change due to their different
coefficients of linear expansion
,◉ Pyrometers Answer: Instruments that measure temperatures at
the surface of an object. Typically used for ranges above that suitable
for other kinds of thermometers.
◉ Thermoelectric Pyrometer Answer: Uses a thermocouple to
produce an electric voltage which is proportional to temperature.
◉ Infrared thermometer Answer: A digital device capable of
measuring the temperature of an object at a distance by detecting its
infrared energy emissions.
◉ Specific Heat Answer: The amount of energy required to raise the
temperature of 1 gram of a substance by 1 degree celcius
◉ sensible heat Answer: The heat energy that causes a change in
temperature of a substance but does not contribute to a change in
state
◉ latent heat Answer: heat absorbed or radiated during a change of
phase at a constant temperature and pressure
◉ The specific heat of iron is 0.544 kJ/kg°C. How much heat is given
off if the temperature of a 1.5kg block drops from 80°C to 25°C?
Answer: 44.88kJ
, ◉ coefficient of linear expansion Answer: The change in length per
unit, per degree rise in temperature.
◉ A large diameter steel steam pipe is erected at 20°C and will carry
steam at a
temperature of 320°C. At operating temperatures, how much linear
expansion
will there be in a 30 m long straight section of this steam line?
Answer: 0.108 m
◉ Conduction Answer: Conduction involves the transfer of heat
energy in two ways:
1. From molecule to molecule within an individual substance.
2. From the molecules of one body to those of another body in direct
contact with the first body.
◉ Convection Answer: The transfer of heat by the movement of a
fluid.
◉ Convection Current Answer: The movement of a fluid, due to the
action of gravity on a fluid varying in density, and caused by the
application of heat.
