# Class 11th Physics – 12 Thermodynamics

#### Second law of thermodynamics as stated by ____ put a limitation to the co-efficient of performance of a refrigerator.

Correct! Wrong!

Second law of thermodynamics as stated by Clausius put a limitation to the co-efficient of performance of a refrigerator.

#### The physical quantity ____ is defined using ____ law of thermodynamics.

Correct! Wrong!

The physical quantity "temperature" is defined using zeroth law of thermodynamics.

#### At triple point of water, ice water and water vapour co exist at the same temperature. Then heat flows from ____

Correct! Wrong!

Even though the three substances are in three different states, they all are at the same temperature. Hence, there will be no exchange of heat among the three different substances.

#### If two objects "P" and "Q" are in thermal equilibrium, then ____.

Correct! Wrong!

If temperatures of two bodies are same, they are in thermal equilibrium. This is true whether their masses and volumes are equal or not.

#### ____ is an example of an extensive variable.

Correct! Wrong!

Mass of a gas is an example of an extensive variable. Pressure, temperature and molar heat capacity of a gas are size independent and they are intensive variables. Whereas mass of a gas is independent of size and hence it is an extensive variable.

#### A gas is said to be in mechanical equilibrium if ____

Correct! Wrong!

A gas is in mechanical equilibrium if the pressure of the gas is uniform throughout the system and do not change with time.

#### The process in which the system exchanges heat with its surroundings and always maintain the same temperature is known as ____.

Correct! Wrong!

In an isothermal process, the system regularly and continuously exchanges heat with its surroundings and maintains the same temperature throughout.

#### Efficiency of a heat engine can never be 100%. This is because of ____

Correct! Wrong!

Second law of thermodynamics prohibits any heat engine to have 100% efficiency.

#### ____ is an intensive variable

Correct! Wrong!

Pressure is an intensive variable. If a system is divided into two halves, its volume, quantity of substance and heat capacity all change. But, no change is found in the pressure of the gas.

#### According to ____ law of thermodynamics, the energy supplied to the system goes in partly to increase the internal energy of the system and the rest in work of the environment.

Correct! Wrong!

According to first law of thermodynamics, the energy supplied to the system goes in partly to increase the internal energy of the system and the rest in work of the environment.

#### ____ and ____ are the two modes of energy transfer to a thermodynamic system

Correct! Wrong!

Heat and work are the two modes of energy transfer to a thermodynamic system.

#### A heat engine receives heat from a ____ and returns heat to a ____, whereas, a refrigerator receive heat from a ____ and returns heat to a ____.

Correct! Wrong!

A heat engine receives heat from a hot reservoir and returns heat to a cold reservoir, whereas, a refrigerator receive heat from a cold reservoir and returns heat to a hot reservoir.

#### The general principle of conservation of energy is given by ____.

Correct! Wrong!

The general principle of conservation of energy is given by the mathematical equation represented as - ΔQ − ΔW = ΔU, where ΔQ is the heat supplied to the system by the surroundings, ΔW is the work done by the system on the surroundings and ΔU is the change in internal energy of the system.

#### ____ wall does not allow flow of heat energy through it and ____ wall allow heat to pass through.

Correct! Wrong!

Adiabatic wall does not allow heat energy to pass through it and a diathermic wall allows heat to pass through it.

#### Heating of a gas in a container at constant pressure is an example of ____ process.

Correct! Wrong!

A process that takes place at constant pressure is known as isobaric process. If a process is taking place at constant volume then it is known as isochoric. If a process is taking place without any exchange of heat with surroundings, then the process is known as adiabatic process.

#### When a body receives heat ____

Correct! Wrong!

When a body receives heat energy, it is sometimes used to increase the temperature of the body and sometimes it is used to change the state of the body. But in both the cases, the internal energy of the body increases.

#### In an isothermal process, if an ideal gas in a container absorbs heat, then ____.

Correct! Wrong!

In an isothermal process, the temperature of the system remains the same. For an ideal gas, internal energy depends only on the temperature of the gas. Hence there will be no change in the internal energy of an ideal gas in an isothermal process. So the absorbed heat is used in doing work as the gas expands.

#### Equation of state for an ideal gas is ____

Correct! Wrong!

The equation of state for an ideal gas is PV = μRt

#### Internal energy U of any gas in a system can change through two modes of energy transfer which is heat and work.

Correct! Wrong!

Internal energy of a gas is the sum of the kinetic energy and the inter molecular potential energy of the molecules of the gas. In an ideal gas, intermolecular forces do not exist and hence it possesses no intermolecular potential energy and hence the internal energy is only the kinetic energy. Thus, internal energy U of any gas in a system can change through two modes of energy transfer which is heat and work.

#### Body "P" is at 600C and body Q is at 300C. If both of them are brought in contact with each other, initially they are ____ and after a lapse of sufficient time they ____

Correct! Wrong!

Body "P" is at 600C and body Q is at 300C. If both of them are brought in contact with each other, initially they are not in thermal equilibrium and after a lapse of sufficient time they both attain a common temperature.

#### A process of converting heat completely into work is inconsistent with ____

Correct! Wrong!

According to first law of thermodynamics or law of conservation of energy, heat energy can be completely converted to work. But the said process is inconsistent with second law of thermodynamics.

#### ____ is not a thermodynamic state variable of a system of gas.

Correct! Wrong!

Pressure, volume, temperature and internal energy of a gas all are thermodynamic state variables. But heat is not a state variable as it depends on the path through which the thermodynamic system is taken.

#### a) First law of thermodynamics is from "law of conservation of energy" b) In nature, all processes allowed by first law of thermodynamics do take place

Correct! Wrong!

First law of thermodynamics is from "law of conservation of energy". There are many processes allowed by first law of thermodynamics that do not take place.

#### When a thermodynamic system is taken from one thermodynamic state to another thermodynamic state ____ is independent of the path.

Correct! Wrong!

Internal energy of a system is a state function. It will not depend on the path through which the system is taken

#### According to first law of thermodynamics, the energy supplied to the system goes in partly to increase the internal energy of the system and the rest in work of the environment.

Correct! Wrong!

According to first law of thermodynamics, the energy supplied to the system goes in partly to increase the internal energy of the system and the rest in work of the environment. The general principle of conservation of energy is given by the mathematical equation represented as - ΔQ − ΔW = ΔU, where ΔQ is the heat supplied to the system by the surroundings, ΔW is the work done by the system on the surroundings and ΔU is the change in internal energy of the system.

#### ____ is a device in which the working substance undergoes a ____ process resulting in conversion of heat energy to mechanical energy.

Correct! Wrong!

Heat engine is a device in which the working substance undergoes a cyclic process resulting in conversion of heat energy to mechanical energy.

#### A quasi static process is ____.

Correct! Wrong!

A process that is infinitely slow and the system is in equilibrium state at every stage is known as quasi-static process.

#### No exchange of heat takes place between two gases "A" and "B" when they are separated by an adiabatic wall. Similarly, no exchange of heat takes place between two gases "B" and "C" when they are separated by an adiabatic wall Then gases "A" and "C" ____

Correct! Wrong!

Since the gases are separated by adiabatic walls, it is not possible to know whether gases "A" "B" and "C" are in thermal equilibrium or not.

#### State of a thermodynamic system is said to be an equilibrium state if ____

Correct! Wrong!

State of a thermodynamic system is said to be an equilibrium state if pressure and temperature are uniform throughout the system and do not change with time.

#### If a system is taken through a process in which ____ is maintained constant, for an ideal gas, ΔQ = ΔW.

Correct! Wrong!

If a system is taken through a process in which ΔU = 0 or for an isothermal expansion of an ideal gas, ΔQ = ΔW.

Class 11th Physics - 12 Thermodynamics
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