General Physics III — 2025 Past Questions

University of Ilorin PHY103: 42 questions.

Topics: Heat and Temperature, Gas Law, Second Law of Thermodynamics, First Law of Thermodynamics, Elasticity, Thermodynamics Systems, Zeroth Law of Thermodynamics, Kinetic Theory of Gases, Thermal Conductivity, Viscosity, Kinetic Theory of Gases, Molecular Collision, and Mean Free Path

1. What is an isolated system
   1. A system that exchanges both matter and energy with its surroundings
   2. A system that exchanges only energy with its surroundings
   3. A system that does not exchange matter or energy with its surroundings
   4. A system that exchanges only matter with its surroundings
2. What are the freezing and boiling points of water in Celsius, Fahrenheit, and Kelvin?
   1. Freezing: 0°C, 32°F, 273.15 K; Boiling: 100°C, 212°F, 373.15 K
   2. Freezing: 0°C, 32°F, 273 K; Boiling: 100°C, 212°F, 373 K
   3. Freezing: 0°C, 32°F, 273.15 K; Boiling: 100°C, 200°F, 373.15 K
   4. Freezing: -10°C, 32°F, 273.15 K; Boiling: 100°C, 212°F, 373.15 K
3. Convert average human temperature of 98.6°F to Celsius
   1. 37°C
   2. 112°C
   3. 32.5°C
   4. 44°C
4. If a piece of metal is heated from 50°F to 150°F, calculate the temperature difference in Celsius as P and in Kelvin as Q, and evaluate (P - Q):
   1. 0
   2. 40.2
   3. 56.3
   4. 72.5
5. In a system where Avogadro's law is obeyed, the initial number of molecules n1 is tripled. Find the final volume
   1. n2/3
   2. V2/3
   3. 3V1
   4. V1/3
6. Convert an average human temperature of 37°C to Fahrenheit:
   1. 98.6°F
   2. 100°F
   3. 96.6°F
   4. 102°F
7. The temperature difference between the inside and outside of a home is 57.0°F. Express this temperature difference in Celsius
   1. 27.3°C
   2. 29.5°C
   3. 31.7°C
   4. 39.4°C
8. Determine the pressure change when a constant volume of gas at 2.00 atm is heated from 30.0°C to 40.0°C
   1. 2.07 atm
   2. 2.10 atm
   3. 2.09 atm
   4. 2.05 atm
9. In a system where Avogadro's law is obeyed and the initial number of molecules n1 is tripled, find the initial volume
   1. 3V1
   2. n2/3
   3. V2/3
   4. V1/3
10. Calculate the work done by a system if 500 J is added to it and the change in internal energy of the system is 350 J
    1. 150 J
    2. 850 J
    3. 500 J
    4. 350 J
11. A 2.0 mg droplet of liquid nitrogen is present in a 30 mL tube sealed at very low temperature. What will the nitrogen pressure in the tube be when it is warmed to 20°C?
    1. 0.0573 atm
    2. 0.573 atm
    3. 5.73 atm
    4. 57.3 atm
12. The only elastic modulus that applies to liquids is
    1. Bulk modulus
    2. Young's modulus
    3. Shear modulus
    4. Tensile modulus
13. A spiral spring was stretched by 4.0 mm when a force of 5.0 N was attached to it. What will be the extension if the force is increased by 80%?
    1. 4.5 mm
    2. 6.7 mm
    3. 7.2 mm
    4. 5.5 mm
14. The temperature difference between the inside and outside of a car is 31.7°C. Obtain this difference on the Fahrenheit scale.
    1. –338.67°F
    2. –169.67°F
    3. 57.06°F
    4. –259.67°F
15. A metal sheet was heated from 50°F to 150°F. Obtain the change in temperature in the Celsius scale (∆P) and Kelvin scale (∆Q). Find the value (∆P – ∆Q):
    1. Zero
    2. 40.2
    3. 56.3
    4. 72.5
16. Determine the efficiency of a cyclical heat engine where 30 kg of heat is transferred to the surroundings for every 100 kg of heat transferred into the engine.
    1. 100%
    2. 20%
    3. 25%
    4. 50%
17. The average human body temperature is 37°C. What's the value on the Fahrenheit scale?
    1. 98.6°F
    2. 100°F
    3. 96.6°F
    4. 102°F
18. What's the efficiency of a heat engine that uses 80 kJ of heat for every 100 kJ of heat transfer from the hot reservoir?
    1. 20%
    2. 25%
    3. 50%
    4. 75%
19. Determine the efficiency of a heat engine where 80 kJ of heat is transferred to the surroundings for every 100 kJ transferred to the engine.
    1. 100%
    2. 20%
    3. 25%
    4. 75%
20. Temperature is a measure of _____
    1. None of the above
    2. Motion of the atoms or molecules
    3. Heat content of a substance
    4. Total energy of a substance
21. A system subjected to heat energy contains 4,000 molecules with an average kinetic energy of 5.0 × 10^-17 joules. Calculate the temperature required to reach that kinetic energy.
    1. 2.41 × 10^6 K
    2. 2.41 × 10^5 K
    3. 2.41 × 10^4 K
    4. 2.41 × 10^3 K
22. Determine the efficiency of a heat engine where 30 J of work is done for every 100 J of heat absorbed from the hot reservoir.
    1. 100%
    2. 20%
    3. 25%
    4. 75%
23. A 2.0 mg droplet of liquid nitrogen is present in a 30 mL tube sealed at a very low temperature. What will be the nitrogen pressure in the tube when it is warmed to 20°C?
    1. 0.0573 atm
    2. 0.573 atm
    3. 5.73 atm
    4. 57.3 atm
24. If the number of molecules n1 of a fixed mass of gas is tripled, find the final volume provided that it obeys Avogadro's law.
    1. 3V1
    2. 0.5V1
    3. 2V1
    4. 1.5V1
25. The average human body temperature is 98.6°F. What is its equivalent value on the Celsius scale?
    1. 48°C
    2. 37°C
    3. 30°C
    4. 40°C
26. The temperature difference between the inside and outside of a home is 57.0°F. Find its value on the Celsius scale.
    1. 31.7°C
    2. 32.7°C
    3. 30.7°C
    4. 33.7°C
27. The velocity with which a spherical ball falls in a viscous liquid when it has attained a non-accelerating state is _______?
    1. Terminal velocity
    2. Uniform velocity
    3. Viscous velocity
    4. Critical velocity
28. The form of electromagnetic wave similar to light or radio waves and does not require a medium for its transmission is _____?
    1. Radiation
    2. Convection
    3. Conduction
    4. Evaporation
29. The SI unit of temperature is ____?
    1. Celsius (°C)
    2. Kelvin
    3. Fahrenheit (°F)
    4. Rankine (°R)
30. In thermodynamics, a boundary can be defined as ____?
    1. The surface that separates the system from its surroundings
    2. The region where heat transfer occurs
    3. The point of maximum temperature in a system
    4. The interface between different phases of matter
31. Energy can only flow between two objects in thermal contact if:
    1. They are of different elements
    2. There is a temperature difference
    3. They are at thermal equilibrium
    4. They have different masses
32. In thermodynamics, an isolated system can be defined as:
    1. A system that exchanges only energy with its surroundings
    2. A system that has no connection with the surroundings
    3. A system that exchanges both matter and energy with its surroundings
    4. A system that exchanges only matter with its surroundings
33. A force of 5 N was applied to a spring, stretching it by 4 mm. If the force is then increased by 80%, find the new extension.
    1. 7.2 mm
    2. 6.8 mm
    3. 8.0 mm
    4. 5.6 mm
34. Calculate the work done if an object expanded from 200 cm³ to 800 cm³ at atmospheric pressure. (1 atm = 1.01 × 10^5 Pa).
    1. 60.6 J
    2. 6.06 J
    3. 606 J
    4. 0.606 J
35. Convert 37°C to Fahrenheit
    1. 98.6°F
    2. 100°F
    3. 96.6°F
    4. 102°F
36. Convert 98.6°F to Celsius
    1. 37°C
    2. 38°C
    3. 36°C
    4. 39°C
37. Which of these does the Zeroth Law of Thermodynamics talk about?
    1. When A and B separately are in thermal equilibrium with a third system C, then A and B are in thermal equilibrium with one another
    2. Energy cannot be created or destroyed
    3. The entropy of an isolated system always increases
    4. All heat engines have less than 100% efficiency
38. The first law of thermodynamics talks about:
    1. The relationship between internal energy, heat transfer, and work done
    2. The entropy of an isolated system always increases
    3. If two systems are in thermal equilibrium with a third system, they are in thermal equilibrium with each other
    4. All heat engines have less than 100% efficiency
39. Which of the thermodynamics laws talks about the entropy of a reversible reaction?
    1. First
    2. Second
    3. Third
    4. Zeroth
40. Unit of pressure in the equation of states in gases:
    1. Pascal
    2. ATM
    3. Bar
    4. Torr
41. Convert 98.6°F to Kelvin
    1. 310.15 K
    2. 300.15 K
    3. 320.15 K
    4. 290.15 K
42. A system contains 4000 molecules. The total kinetic energy of the system is 5.0 × 10⁻¹⁷ J. Calculate the temperature of the system.
    1. 603.86 K
    2. 712.24 K
    3. 534.45 K
    4. 445.72 K

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