Free Thermal Equilibrium and Heat MCQs with Answers
277 Thermal Equilibrium and Heat MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Thermal equilibrium means that bodies in contact have the same temperature and no net heat flows between them. The topic distinguishes heat from temperature, uses the zeroth law of thermodynamics, and covers heat transfer, specific heat capacity, thermal expansion and the conditions for reaching equilibrium.
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277 questions · page 3 of 14
- A. Clausius statement
- B. Kelvin statement
- C. Carnot statement
- D. Boyles statement
Explanation: The Carnot statement of the second law of thermodynamics is derived from the analysis of heat engines and is related to the efficiency of…
Correct answer: Carnot statement- A. reflect more sunlight
- B. absorb more sunlight
- C. are more pleasing to the eye
- D. transmit more light
Explanation: Light-coloured shades have higher reflectivity, meaning they reflect a larger portion of incoming sunlight away from the building.
Correct answer: reflect more sunlight- A. cyclic process
- B. operated at certain temperature difference
- C. petrol must be used
- D. both (a) and (b)
Explanation: A heat engine works by utilizing a cyclic process, where it continuously operates in a repeating sequence.Additionally, a heat engine…
Correct answer: both (a) and (b)- A. Specific heat of the slab
- B. cross-sectional area of the slab
- C. thermal conductivity of the slab
- D. temperature difference between opposite faces of the slab
Explanation: The first law of thermodynamics is a consequence of the conservation of energy, which states that energy cannot be created or destroyed…
Correct answer: Specific heat of the slab- A. isobaric
- B. isochoric
- C. adiabatic
- D. isothermal
Explanation: an isothermal process, the temperature remains constant throughout the process.
Correct answer: isothermal- A. isothermal
- B. isobaric
- C. isochoric
- D. adiabatic
Explanation: The process in thermodynamics during which the volume of a system remains constant is referred to as an isochoric process.
Correct answer: isochoric- A. Celsius scale
- B. Fahrenheit scale
- C. Centigrade scale
- D. Thermodynamic scale
Explanation: The thermodynamic temperature scale, also known as the Kelvin scale, is independent of the nature of the working substance.
Correct answer: Thermodynamic scale- A. Electric generator
- B. Refrigerator
- C. Carnot engine
- D. Electric motor
Explanation: A heat engine converts heat energy into mechanical work, and it operates in a cycle.
Correct answer: Refrigerator- A. Isotherm
- B. Adiabatic
- C. Both a and b
- D. Either a or b
Explanation: An isotherm is a curve on a graph representing the variation of pressure or other parameters while keeping the temperature constant during…
Correct answer: Isotherm- A. 46°
- B. -40°
- C. 32°
- D. 40°
Explanation: Fahrenheit and Celsius scales have the same reading at -40°. This is the point where the numerical value in Fahrenheit is equal to the…
Correct answer: -40°- A. Temperature of source
- B. Temperature of sink
- C. Both a and b
- D. Working substance
Explanation: The efficiency of a heat engine depends on both the temperature of the source (where heat is absorbed) and the temperature of the sink…
Correct answer: Both a and b- A. Input stroke
- B. Exhaust stroke
- C. Power stroke
- D. All of these
Explanation: The third stroke of a petrol engine is the power stroke. It is the stage where the ignited fuel-air mixture expands, exerting force on the…
Correct answer: Power stroke- A. 25% to 30%
- B. 30% to 35%
- C. 35% to 40%
- D. 30% to 40%
Explanation: The typical efficiency range for a diesel engine is between 35% and 40%.
Correct answer: 35% to 40%- A. JK
- B. J^-1K
- C. JK^-¹
- D. J^-1K^-¹
Explanation: The unit of entropy is joules per kelvin (J^-1K^-¹). Entropy is a measure of the amount of energy in a system that is unavailable to do…
Correct answer: J^-1K^-¹- A. Adiabatic process
- B. Isobaric process
- C. Isothermal process
- D. Isochoric process
Explanation: In an isochoric (constant volume) process, there is no change in volume, and thus no work is done by or on the system.
Correct answer: Isochoric process- A. Increases
- B. Decreases
- C. Remains the same
- D. 0
Explanation: Entropy is a measure of the disorder or randomness of a system. When heat is removed from the system, the disorder decreases, leading to a…
Correct answer: Decreases- A. Irreversible
- B. Reversible
- C. Either a or b
- D. Cyclic
Explanation: An irreversible process is one that cannot be retraced or undone. In such processes, entropy always increases and the system and…
Correct answer: Irreversible- A. 273.16 K
- B. 273.16°F
- C. 273.16°C
- D. 270°C
Explanation: The triple point of water is the temperature and pressure at which water can coexist in all three phases: solid, liquid, and vapor.
Correct answer: 273.16°C- A. Petrol engine
- B. Carnot engine
- C. Diesel engine
- D. Watt's steam engine
Explanation: The Carnot engine has the highest theoretical efficiency among heat engines operating between two temperature reservoirs.
Correct answer: Carnot engine- A. Depends upon T and Ta
- B. Depends upon the working substance
- C. Is 100% if T2 =0K
- D. None of these
Explanation: The efficiency of the Carnot engine depends only on the temperatures of the hot and cold reservoirs, T and Ta , respectively.
Correct answer: None of these