Termodinamika Practice Questions
UN (Indonesia) · UN Fisika · 147 free MCQs with instant results and detailed explanations.
147
Total
57
Easy
70
Medium
20
Hard
Start Practicing Termodinamika
Take a timed quiz or customize your practice session
Sample Questions from Termodinamika
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What is the primary principle behind the First Law of Thermodynamics?
A.
Energy cannot be created or destroyed.
B.
Heat always flows from cold to hot.
C.
Work done on a system increases its temperature.
D.
Gases always expand when heated.
Show Answer & Explanation
Correct Answer: A
The First Law of Thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another. This emphasizes the conservation of energy principle in thermodynamic processes.
Q2
Easy
A gas expands in a piston at constant pressure of 100 kPa, doing 500 J of work. What is the change in internal energy if no heat is added to the system?
A.
500 J
B.
-500 J
C.
0 J
D.
1000 J
Show Answer & Explanation
Correct Answer: B
According to the First Law of Thermodynamics, ฮU = Q - W. Since no heat is added (Q = 0), the change in internal energy ฮU = 0 - 500 J = -500 J, indicating that energy is lost from the system.
Q3
Easy
When a gas is compressed adiabatically, which of the following statements is true?
A.
The temperature of the gas decreases.
B.
No heat is exchanged with the surroundings.
C.
The gas does no work on the piston.
D.
The pressure of the gas remains constant.
Show Answer & Explanation
Correct Answer: B
In an adiabatic process, there is no heat exchange with the surroundings. This means that all the work done on the gas results in an increase in temperature, not a decrease, contradicting options A and C.
Q4
Medium
What is the primary factor that affects the efficiency of a heat engine?
A.
Temperature difference between heat source and sink
B.
Size of the engine
C.
Type of fuel used
D.
Material of engine components
Show Answer & Explanation
Correct Answer: A
The efficiency of a heat engine primarily depends on the temperature difference between the heat source and the heat sink. Higher temperature differences typically lead to higher efficiencies.
Q5
Medium
A gas expands isothermally at 300 K from a volume of 2.0 mยณ to 4.0 mยณ. If the pressure of the gas initially is 100 kPa, what is the final pressure?
A.
50 kPa
B.
100 kPa
C.
200 kPa
D.
75 kPa
Show Answer & Explanation
Correct Answer: A
According to Boyle's Law (P1V1 = P2V2), when the temperature is constant, the pressure and volume of a gas are inversely proportional. Thus, P2 = (P1 * V1) / V2 = (100 kPa * 2.0 mยณ) / 4.0 mยณ = 50 kPa.
Q6
Medium
In a closed system, if 500 J of heat is added to the system and 200 J of work is done by the system, what is the change in internal energy according to the first law of thermodynamics?
A.
300 J
B.
500 J
C.
200 J
D.
700 J
Show Answer & Explanation
Correct Answer: A
According to the first law of thermodynamics, ฮU = Q - W. Here, Q = 500 J and W = 200 J. Therefore, ฮU = 500 J - 200 J = 300 J.
Q7
Medium
Which of the following statements correctly describes an adiabatic process?
A.
No heat is transferred into or out of the system.
B.
Temperature remains constant throughout the process.
C.
Pressure remains constant during the process.
D.
The system is in thermal equilibrium with its surroundings.
Show Answer & Explanation
Correct Answer: A
An adiabatic process is characterized by the absence of heat transfer to or from the system. This can occur in rapid processes where there is not enough time for heat exchange.
Q8
Hard
A gas expands isothermally in a piston-cylinder assembly from an initial volume of 2 mยณ to a final volume of 6 mยณ at a temperature of 300 K. Calculate the work done by the gas if the pressure of the gas is 100 kPa.
A.
600 kJ
B.
400 kJ
C.
200 kJ
D.
800 kJ
Show Answer & Explanation
Correct Answer: B
The work done during an isothermal expansion of an ideal gas is calculated using the formula W = P(Vf - Vi), where P is pressure, Vf is final volume, and Vi is initial volume. Here, W = 100 kPa * (6 mยณ - 2 mยณ) = 100 kPa * 4 mยณ = 400 kJ.
Q9
Hard
A cylinder contains 2 moles of an ideal gas at a temperature of 300 K. If the gas is compressed isothermally to half its initial volume, what will be the final pressure of the gas? (Use R = 8.31 J/(molยทK))
A.
4.15 atm
B.
2.07 atm
C.
8.31 atm
D.
1.04 atm
Show Answer & Explanation
Correct Answer: A
According to the ideal gas law, PV = nRT. When the volume is halved and temperature remains constant, the pressure doubles. The initial pressure can be calculated and then doubled.
Q10
Hard
In an adiabatic process, a gas expands from a volume of 1.0 mยณ to 3.0 mยณ and does 600 J of work. What is the change in internal energy of the gas?
A.
600 J
B.
0 J
C.
-600 J
D.
300 J
Show Answer & Explanation
Correct Answer: C
In an adiabatic process, the change in internal energy (ฮU) is equal to the work done (W) on the gas. Since the gas is expanding, the work done by the gas is positive, which means internal energy decreases by the same amount.
Showing 10 of 147 questions. Start a quiz to practice all questions with scoring and timer.
Practice All 147 Questions →Other UN (Indonesia) Subjects
Termodinamika โ UN (Indonesia) UN Fisika Practice Questions Online
This page contains 147 practice MCQs for the chapter Termodinamika in UN (Indonesia) UN Fisika. The questions are organized by difficulty โ 57 easy, 70 medium, 20 hard โ so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.