Thermodynamics MCQ Quiz - Objective Question with Answer for Thermodynamics - Download Free PDF

The correct answer is Decreases.

Key Points

• When steam condenses into water, it undergoes a phase change from gas to liquid, releasing latent heat in the process.
• This release of latent heat leads to a decrease in the internal energy of the system.
• The internal energy of a system is directly related to the kinetic and potential energy of its molecules; in the liquid state, molecules have lower energy than in the gaseous state.
• The process of condensation is exothermic, meaning energy is released to the surroundings during the phase change.
• This decrease in internal energy does not affect the temperature of the water until the phase change is complete.

Additional Information

• Internal Energy:
  • Internal energy is the sum of the kinetic and potential energies of the molecules in a system.
  • It depends on the state of matter (solid, liquid, gas) and temperature.
  • In gases, molecules have higher kinetic energy compared to liquids or solids.
• Latent Heat:
  • Latent heat is the energy absorbed or released during a phase change without a change in temperature.
  • In condensation, latent heat is released as the system transitions from gas to liquid.
• Phase Change:
  • A phase change is the transformation of matter from one state to another, such as from solid to liquid or liquid to gas.
  • Common phase changes include melting, freezing, vaporization, condensation, sublimation, and deposition.
• Exothermic and Endothermic Processes:
  • Exothermic processes release energy to the surroundings (e.g., condensation, freezing).
  • Endothermic processes absorb energy from the surroundings (e.g., evaporation, melting).

CONCEPT:

Zeroth Law of Thermodynamics

• The Zeroth Law of Thermodynamics deals with the concept of thermal equilibrium.
• It states that if two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other.
• This law forms the basis for the definition of temperature.
• It implies that temperature is the property that determines whether a system is in thermal equilibrium or not.

EXPLANATION

• The Zeroth Law provides the foundation for the measurement of temperature.
• It allows us to use a thermometer as the third system to measure the temperature of other systems.
• Temperature: This is the correct answer, as the Zeroth Law establishes the concept of temperature as a measurable property.

Therefore, the correct answer is Temperature.

The correct answer is First Law of Thermodynamics.

Key Points

• The First Law of Thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic processes.
• It states that energy cannot be created or destroyed in an isolated system.
• The change in the internal energy of a system (ΔU) is equal to the heat added to the system (ΔQ) minus the work done by the system on its surroundings (ΔW).
• This can be mathematically expressed as ΔQ = ΔU + ΔW.

Additional Information

• Internal Energy (U)
  • It is the total energy contained within a system, including kinetic and potential energy at the molecular level.
  • Changes in internal energy can result from heat transfer or work done.
• Heat (Q)
  • It is a form of energy transfer between systems due to a temperature difference.
  • Heat transfer can occur through conduction, convection, or radiation.
• Work (W)
  • In thermodynamics, work is the energy transferred when an object is moved by a force.
  • Positive work is done by the system when it expands against an external pressure.
• Applications of the First Law
  • It is used to analyze various thermodynamic cycles such as the Carnot cycle, Otto cycle, and refrigeration cycles.
  • It helps in understanding the energy efficiency of engines and other systems.
• Limitations
  • The First Law does not provide information about the direction of processes or the feasibility of reactions.
  • It does not explain entropy changes or the Second Law of Thermodynamics.

The correct answer is Temperature.

Key Points

• The Zeroth Law of Thermodynamics states that if two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.
• This law establishes the concept of temperature as a measurable and comparable quantity.
• The Zeroth Law allows for the construction of thermometers to measure temperature based on the principle of thermal equilibrium.
• Temperature is a scalar quantity that indicates the degree of hotness or coldness of a body or environment.
• It is critical for defining the state of a system in thermodynamics and is key to understanding energy transfer processes like heat.

Additional Information

• Thermal Equilibrium:
  • Two systems are in thermal equilibrium if there is no net flow of thermal energy between them.
  • It is a foundational concept in thermodynamics and a prerequisite for measuring temperature accurately.
• Thermometers:
  • Devices used to measure temperature based on physical properties like expansion of mercury or electrical resistance.
  • They rely on the Zeroth Law to ensure consistent and accurate readings.
• Temperature Scales:
  • Common scales include Celsius, Fahrenheit, and Kelvin.
  • Kelvin is the SI unit of temperature and starts from absolute zero, the lowest theoretically possible temperature.
• Thermodynamics:
  • A branch of physics that deals with the relationships between heat, work, and energy.
  • The Zeroth Law complements the First, Second, and Third Laws of Thermodynamics in understanding energy systems.

The correct answer is ∆U.

Key Points

• In a cyclic process, the system returns to its initial state after completing the cycle, meaning the change in internal energy (∆U) is zero.
• Internal energy (U) is a state function, and its value depends only on the state of the system, not on the path taken to reach that state.
• The first law of thermodynamics states: ∆U = Q - W, where Q is heat added to the system, and W is work done by the system.
• For a cyclic process, the initial and final states are the same, so the net internal energy change (∆U) is zero, regardless of the values of Q and W.
• Examples of cyclic processes include Carnot cycles, Otto cycles, and Rankine cycles commonly used in thermodynamics and heat engines.

Additional Information

• Cyclic Process
  • A thermodynamic process where the system undergoes changes but eventually returns to its initial state.
  • Examples include processes in heat engines, refrigeration cycles, and power plants.
• Internal Energy (U)
  • The total energy contained within a system, including kinetic and potential energy at the molecular level.
  • It is a state function and depends only on the current state of the system (temperature, pressure, volume).
• First Law of Thermodynamics
  • Expresses the principle of conservation of energy: energy cannot be created or destroyed; it can only change forms.
  • Mathematically: ∆U = Q - W, where Q is the heat added to the system, and W is the work done by the system.
• Work (W) and Heat (Q)
  • Work is the energy transferred by a system to its surroundings due to macroscopic forces.
  • Heat is the energy transferred between systems due to a temperature difference.

The correct answer is First Law of Thermodynamics.

Key Points

• The First Law of Thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic processes.
• It states that energy cannot be created or destroyed in an isolated system.
• The change in the internal energy of a system (ΔU) is equal to the heat added to the system (ΔQ) minus the work done by the system on its surroundings (ΔW).
• This can be mathematically expressed as ΔQ = ΔU + ΔW.

Additional Information

• Internal Energy (U)
  • It is the total energy contained within a system, including kinetic and potential energy at the molecular level.
  • Changes in internal energy can result from heat transfer or work done.
• Heat (Q)
  • It is a form of energy transfer between systems due to a temperature difference.
  • Heat transfer can occur through conduction, convection, or radiation.
• Work (W)
  • In thermodynamics, work is the energy transferred when an object is moved by a force.
  • Positive work is done by the system when it expands against an external pressure.
• Applications of the First Law
  • It is used to analyze various thermodynamic cycles such as the Carnot cycle, Otto cycle, and refrigeration cycles.
  • It helps in understanding the energy efficiency of engines and other systems.
• Limitations
  • The First Law does not provide information about the direction of processes or the feasibility of reactions.
  • It does not explain entropy changes or the Second Law of Thermodynamics.

The correct answer is Decreases.

Key Points

• When steam condenses into water, it undergoes a phase change from gas to liquid, releasing latent heat in the process.
• This release of latent heat leads to a decrease in the internal energy of the system.
• The internal energy of a system is directly related to the kinetic and potential energy of its molecules; in the liquid state, molecules have lower energy than in the gaseous state.
• The process of condensation is exothermic, meaning energy is released to the surroundings during the phase change.
• This decrease in internal energy does not affect the temperature of the water until the phase change is complete.

Additional Information

• Internal Energy:
  • Internal energy is the sum of the kinetic and potential energies of the molecules in a system.
  • It depends on the state of matter (solid, liquid, gas) and temperature.
  • In gases, molecules have higher kinetic energy compared to liquids or solids.
• Latent Heat:
  • Latent heat is the energy absorbed or released during a phase change without a change in temperature.
  • In condensation, latent heat is released as the system transitions from gas to liquid.
• Phase Change:
  • A phase change is the transformation of matter from one state to another, such as from solid to liquid or liquid to gas.
  • Common phase changes include melting, freezing, vaporization, condensation, sublimation, and deposition.
• Exothermic and Endothermic Processes:
  • Exothermic processes release energy to the surroundings (e.g., condensation, freezing).
  • Endothermic processes absorb energy from the surroundings (e.g., evaporation, melting).

The correct answer is Temperature.

Key Points

• The Zeroth Law of Thermodynamics states that if two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.
• This law establishes the concept of temperature as a measurable and comparable quantity.
• The Zeroth Law allows for the construction of thermometers to measure temperature based on the principle of thermal equilibrium.
• Temperature is a scalar quantity that indicates the degree of hotness or coldness of a body or environment.
• It is critical for defining the state of a system in thermodynamics and is key to understanding energy transfer processes like heat.

Additional Information

• Thermal Equilibrium:
  • Two systems are in thermal equilibrium if there is no net flow of thermal energy between them.
  • It is a foundational concept in thermodynamics and a prerequisite for measuring temperature accurately.
• Thermometers:
  • Devices used to measure temperature based on physical properties like expansion of mercury or electrical resistance.
  • They rely on the Zeroth Law to ensure consistent and accurate readings.
• Temperature Scales:
  • Common scales include Celsius, Fahrenheit, and Kelvin.
  • Kelvin is the SI unit of temperature and starts from absolute zero, the lowest theoretically possible temperature.
• Thermodynamics:
  • A branch of physics that deals with the relationships between heat, work, and energy.
  • The Zeroth Law complements the First, Second, and Third Laws of Thermodynamics in understanding energy systems.

The correct answer is ∆U.

Key Points

• In a cyclic process, the system returns to its initial state after completing the cycle, meaning the change in internal energy (∆U) is zero.
• Internal energy (U) is a state function, and its value depends only on the state of the system, not on the path taken to reach that state.
• The first law of thermodynamics states: ∆U = Q - W, where Q is heat added to the system, and W is work done by the system.
• For a cyclic process, the initial and final states are the same, so the net internal energy change (∆U) is zero, regardless of the values of Q and W.
• Examples of cyclic processes include Carnot cycles, Otto cycles, and Rankine cycles commonly used in thermodynamics and heat engines.

Additional Information

• Cyclic Process
  • A thermodynamic process where the system undergoes changes but eventually returns to its initial state.
  • Examples include processes in heat engines, refrigeration cycles, and power plants.
• Internal Energy (U)
  • The total energy contained within a system, including kinetic and potential energy at the molecular level.
  • It is a state function and depends only on the current state of the system (temperature, pressure, volume).
• First Law of Thermodynamics
  • Expresses the principle of conservation of energy: energy cannot be created or destroyed; it can only change forms.
  • Mathematically: ∆U = Q - W, where Q is the heat added to the system, and W is the work done by the system.
• Work (W) and Heat (Q)
  • Work is the energy transferred by a system to its surroundings due to macroscopic forces.
  • Heat is the energy transferred between systems due to a temperature difference.

CONCEPT:

Zeroth Law of Thermodynamics

• The Zeroth Law of Thermodynamics deals with the concept of thermal equilibrium.
• It states that if two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other.
• This law forms the basis for the definition of temperature.
• It implies that temperature is the property that determines whether a system is in thermal equilibrium or not.

EXPLANATION

• The Zeroth Law provides the foundation for the measurement of temperature.
• It allows us to use a thermometer as the third system to measure the temperature of other systems.
• Temperature: This is the correct answer, as the Zeroth Law establishes the concept of temperature as a measurable property.

Therefore, the correct answer is Temperature.

The correct answer is First Law of Thermodynamics.

Key Points

• The First Law of Thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic processes.
• It states that energy cannot be created or destroyed in an isolated system.
• The change in the internal energy of a system (ΔU) is equal to the heat added to the system (ΔQ) minus the work done by the system on its surroundings (ΔW).
• This can be mathematically expressed as ΔQ = ΔU + ΔW.

Additional Information

• Internal Energy (U)
  • It is the total energy contained within a system, including kinetic and potential energy at the molecular level.
  • Changes in internal energy can result from heat transfer or work done.
• Heat (Q)
  • It is a form of energy transfer between systems due to a temperature difference.
  • Heat transfer can occur through conduction, convection, or radiation.
• Work (W)
  • In thermodynamics, work is the energy transferred when an object is moved by a force.
  • Positive work is done by the system when it expands against an external pressure.
• Applications of the First Law
  • It is used to analyze various thermodynamic cycles such as the Carnot cycle, Otto cycle, and refrigeration cycles.
  • It helps in understanding the energy efficiency of engines and other systems.
• Limitations
  • The First Law does not provide information about the direction of processes or the feasibility of reactions.
  • It does not explain entropy changes or the Second Law of Thermodynamics.

The correct answer is Decreases.

Key Points

• When steam condenses into water, it undergoes a phase change from gas to liquid, releasing latent heat in the process.
• This release of latent heat leads to a decrease in the internal energy of the system.
• The internal energy of a system is directly related to the kinetic and potential energy of its molecules; in the liquid state, molecules have lower energy than in the gaseous state.
• The process of condensation is exothermic, meaning energy is released to the surroundings during the phase change.
• This decrease in internal energy does not affect the temperature of the water until the phase change is complete.

Additional Information

• Internal Energy:
  • Internal energy is the sum of the kinetic and potential energies of the molecules in a system.
  • It depends on the state of matter (solid, liquid, gas) and temperature.
  • In gases, molecules have higher kinetic energy compared to liquids or solids.
• Latent Heat:
  • Latent heat is the energy absorbed or released during a phase change without a change in temperature.
  • In condensation, latent heat is released as the system transitions from gas to liquid.
• Phase Change:
  • A phase change is the transformation of matter from one state to another, such as from solid to liquid or liquid to gas.
  • Common phase changes include melting, freezing, vaporization, condensation, sublimation, and deposition.
• Exothermic and Endothermic Processes:
  • Exothermic processes release energy to the surroundings (e.g., condensation, freezing).
  • Endothermic processes absorb energy from the surroundings (e.g., evaporation, melting).

The correct answer is Temperature.

Key Points

• The Zeroth Law of Thermodynamics states that if two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.
• This law establishes the concept of temperature as a measurable and comparable quantity.
• The Zeroth Law allows for the construction of thermometers to measure temperature based on the principle of thermal equilibrium.
• Temperature is a scalar quantity that indicates the degree of hotness or coldness of a body or environment.
• It is critical for defining the state of a system in thermodynamics and is key to understanding energy transfer processes like heat.

Additional Information

• Thermal Equilibrium:
  • Two systems are in thermal equilibrium if there is no net flow of thermal energy between them.
  • It is a foundational concept in thermodynamics and a prerequisite for measuring temperature accurately.
• Thermometers:
  • Devices used to measure temperature based on physical properties like expansion of mercury or electrical resistance.
  • They rely on the Zeroth Law to ensure consistent and accurate readings.
• Temperature Scales:
  • Common scales include Celsius, Fahrenheit, and Kelvin.
  • Kelvin is the SI unit of temperature and starts from absolute zero, the lowest theoretically possible temperature.
• Thermodynamics:
  • A branch of physics that deals with the relationships between heat, work, and energy.
  • The Zeroth Law complements the First, Second, and Third Laws of Thermodynamics in understanding energy systems.

The correct answer is ∆U.

Key Points

• In a cyclic process, the system returns to its initial state after completing the cycle, meaning the change in internal energy (∆U) is zero.
• Internal energy (U) is a state function, and its value depends only on the state of the system, not on the path taken to reach that state.
• The first law of thermodynamics states: ∆U = Q - W, where Q is heat added to the system, and W is work done by the system.
• For a cyclic process, the initial and final states are the same, so the net internal energy change (∆U) is zero, regardless of the values of Q and W.
• Examples of cyclic processes include Carnot cycles, Otto cycles, and Rankine cycles commonly used in thermodynamics and heat engines.

Additional Information

• Cyclic Process
  • A thermodynamic process where the system undergoes changes but eventually returns to its initial state.
  • Examples include processes in heat engines, refrigeration cycles, and power plants.
• Internal Energy (U)
  • The total energy contained within a system, including kinetic and potential energy at the molecular level.
  • It is a state function and depends only on the current state of the system (temperature, pressure, volume).
• First Law of Thermodynamics
  • Expresses the principle of conservation of energy: energy cannot be created or destroyed; it can only change forms.
  • Mathematically: ∆U = Q - W, where Q is the heat added to the system, and W is the work done by the system.
• Work (W) and Heat (Q)
  • Work is the energy transferred by a system to its surroundings due to macroscopic forces.
  • Heat is the energy transferred between systems due to a temperature difference.