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NCERT Solutions for Class 11 Physics Chapter 11 Thermodynamics

NCERT Solutions for Class 11 Physics Chapter 11 Thermodynamics

Edited By Vishal kumar | Updated on Apr 03, 2025 02:33 PM IST

NCERT Solutions for Class 11 Physics Chapter 11 Thermodynamics: If you are a Class 11 CBSE student and searching for Thermodynamics Class 11 Physics NCERT solutions, this is where it comes in handy. In the Thermodynamics Class 11 chapter, you will study how heat is converted to work and vice versa. For example, electrical energy can be utilized to boil water, and similarly, steam can be utilized to produce electricity. The CBSE NCERT solutions for Class 11 Physics Chapter 11 Thermodynamics carry detailed explanations to exercise questions. Try to solve all these questions yourself before looking at the solutions. NCERT solutions help to improve conceptual knowledge.

This Story also Contains
  1. NCERT Solutions for Class 11 Physics Chapter 11 Thermodynamics
  2. NCERT Solutions for Class 11 Physics Chapter Wise
  3. NCERT Solutions for Class 11 Physics Chapter 12: Download PDF
  4. Additional Questions
  5. Kinetic Theory Chapter 12 Physics NCERT Solutions: Concepts and Important Formulas
  6. Kinetic Theory Class 11 Physics NCERT Topics
  7. NCERT Solutions for Class 11 Physics Chapter Wise
  8. NCERT Solutions for Class 11 Subject Wise
  9. Subject wise NCERT Exemplar solutions
  10. NCERT Solutions for Class 11 Subject wise
  11. Subject wise NCERT Exemplar solutions

The NCERT solution for thermodynamics class 11 physics is prepared by our highly experienced Subject Matter, which gives all the answers to the NCERT Book. Utilizing the NCERT solutions for Class 11, specifically thermodynamics class 11 physics questions and answers, can aid students in practising questions and grasping important syllabus concepts before their exams. These solutions are available for free and can be accessed below.

NCERT Solutions for Class 11 Physics Chapter 11 Thermodynamics

Free download class 11 physics thermodynamics questions and answers pdf for CBSE exam

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NCERT Solutions for Class 11 Physics Chapter 11 Thermodynamics Exercise

Q11.1 A geyser heats water flowing at the rate of 3.0 litres per minute from 27 °C to 77 °C. If the geyser operates on a gas burner, what is the rate of consumption of the fuel if its heat of combustion is 4.0×104 J/g?

Answer:

The volumetric flow of water is

dVdt=3 litres minute1

Density of water = 1000 g/litre

The mass flow rate of water is

dmdt=ρdVdtdmdt=3000 g min1

Specific heat of water, c = 4.2 J g -1 o C -1

The rise in temperature is ΔT=7727=50 oC

The rate of energy consumption will be

dQdt=dmdtcΔTdQdt=3000×4.2×50dQdt=6.3×105 J min1

The heat of combustion of fuel =4.0×104J/g

The rate of consumption of fuel is

6.3×1054×104=15.75 g min1

Q11.2 What amount of heat must be supplied to 2.0×102 kg of nitrogen (at room temperature) to raise its temperature by 45 °C at constant pressure? (Molecular mass of N=28; R=8.3 J mol1K1 .)

Answer:

Mass of nitrogen, m=2.0×102kg=20g

Molar Mass of nitrogen, M N = 28 g

The number of moles is n

n=mMNn=2028n=0.714

As nitrogen is a diatomic gas, it's molar specific heat at constant pressure C P is as follows

CP=7R2CP=7×8.32CP=29.05 J mol1 oC1

Rise in temperature, ΔT=45oC1

The amount of heat Q that must be supplied is

Q=nCPΔTQ=0.714×29.05×45Q=933.38 J

Q11.3 (a) Explain why

(a) Two bodies at different temperatures T1 and T2 if brought in thermal contact do not necessarily settle to the mean temperature (T1+T2)/2 .

Answer:

As we know, heat will flow from the hotter body to the colder body till their temperatures become equal. That temperature will be equal to the mean of the initial temperatures of the bodies only if the two thermal capacities of the two bodies are equal.

Q11.3 (b) Explain why

The coolant in a chemical or a nuclear plant (i.e., the liquid used to prevent the different parts of a plant from getting too hot) should have high specific heat.

Answer:

The coolant should have high specific heat so that it can absorb large amounts of heat without itself getting too hot and its temperature lies in the permissible region. The higher the specific heat, the more heat will be absorbed by the same amount of the material for a given increase in temperature.

Q11.3(c) Explain why

Air pressure in a car tyre increases during driving.

Answer:

As the car is driven, the air inside the tyre heats due to frictional forces. Thus, the temperature of the air inside the tyre increases and this, in turn, increases the pressure inside the tyre.

Q11.3 (d) Explain why

(d) The climate of a harbour town is more temperate than that of a town in a desert at the same latitude.

Answer:

The climate of a harbour town is more temperate than that of a town in a desert at the same latitude because of the formation of sea breezes.

Q11.4 A cylinder with a movable piston contains 3 moles of hydrogen at standard temperature and pressure. The walls of the cylinder are made of a heat insulator, and the piston is insulated by having a pile of sand on it. By what factor does the pressure of the gas increase if the gas is compressed to half its original volume?

Answer:

As the walls of the cylinder and the piston are insulated, the process will be adiabatic. i.e. PVγ would be constant.

Hydrogen is a diatomic gas and therefore γ=1.4

Let the initial and final pressure be P 1 and P 2, respectively.

Let the initial and final volume be T 1 and T 2, respectively.

P1V1γ=P2V2γP2P1=(V1V2)γP2P1=21.4P2P1=2.639

The pressure thus increases by a factor 2.639

Q11.5 In changing the state of a gas adiabatically from an equilibrium state A to another equilibrium state B, an amount of work equal to 22.3 J is done on the system. If the gas is taken from state A to B via a process in which the net heat absorbed by the system is 9.35 cal, how much is the net work done by the system in the latter case ? (Take 1cal=4.19J )

Answer:

In the first case, the process is adiabatic, i.e. ΔQ=0

22.3 J work is done on the system, i.e. Δw=22.3 J

ΔQ=Δu+Δw0=Δu22.3Δu=22.3 J

Since in the latter process as well,l the initial and final states are the same as those in the former process, Δu will remain the same for the latter case.

In the latter case, the net heat absorbed by the system is 9.35 cal

ΔQ=9.35×4.2ΔQ=39.3 J

Δw=ΔQΔuΔw=39.322.3Δw=17.0 J

The network done by the system in the latter case is 17.0 J

Q11.6 Two cylinders A and B of equal capacity are connected to each other via a stopcock. A contains a gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stopcock is suddenly opened. Answer the following :

(a) What is the final pressure of the gas in A and B ?

(b) What is the change in the internal energy of the gas?

(c) What is the change in the temperature of the gas?

(d) Do the intermediate states of the system (before settling to the final equilibrium state) lie on its P-V-T surface?

Answer:

As the entire system is thermally insulated and as free expansion will be taking place the temperature of the gas remains the same. Therefore PV is constant.

Initial Pressure P 1 = 1 atm

Initial Volume, V 1 = V

Final Volume, V 2 = 2V

Final Pressure P 2 will be

P2=P1V1V2P2=P12P2=0.5 atm

The final pressure of the gas in A and B is 0.5 atm.

b) Since the temperature of the gas does not change, its internal energy would also remain the same.

c) As the entire system is thermally insulated and as free expansion will be taking place the temperature of the gas remains the same.

d) The intermediate states of the system do not lie on its P-V-T surface as the process is a free expansion, it is rapid and the intermediate states are non-equilibrium states.

Q11.7 An electric heater supplies heat to a system at a rate of 100W. If system performs work at a rate of 75 joules per second. At what rate is the internal energy increasing?

Answer:

The rate at which heat is supplied ΔQ=100 W

The rate at which work is done ΔW=75 Js1

The rate of change of internal energy is Δu

Δu=ΔQΔwΔu=10075Δu=25 J s1

The internal energy of the system is increasing at a rate of 25 J s -1

Q11.8 A thermodynamic system is taken from an original state to an intermediate state by the linear process shown in Fig. (12.13)

screenshot123

Its volume is then reduced to the original value from E to F by an isobaric process. Calculate the total work done by the gas from D to E to F

Answer:

The work done by the gas as it goes from state D to E to F is equal to the area of triangle DEF

DF is change in pressure = 300 N m -2

FE is change in Volume = 3 m 3

area(DEF)=12×DF×FEarea(DEF)=12×300×3area(DEF)=450 J

The work done is, therefore, 450 J.

The class 11 physics questions and answers for Thermodynamics in Class 11 Physics are highly beneficial for students as they provide a solid foundation in understanding the principles of heat, work, energy, and the laws of thermodynamics. This knowledge not only aids in performing well in exams but also simplifies the comprehension of subsequent chapters in physics, particularly those related to heat and energy transfer. Additionally, problem-solving skills developed through these thermodynamics class 11 physics ncert solutions are transferable and valuable in a wide range of academic and practical scenarios.

NCERT Solutions for Class 11 Physics Chapter Wise

Have you ever wondered why gases appear to expand or how they produce pressure? The Kinetic Theory of Gases explains it by imagining that gases consist of small particles moving about rapidly. Scientists such as Boyle, Newton, Maxwell, and Boltzmann contributed significantly to this theory, which explains gas behavior, their response to changes in temperature and pressure, and even how they flow and mix together.

NCERT solutions for important chapter kinetic theory class 11 chapter 12 physics are created by subject matter experts to offer accurate and clear answers to each and every NCERT exercise problem. Students can build a strong concept by practicing these Kinetic Theory Class 11 Physics solutions. Step-by-step solutions make learning convenient and are provided below.

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NCERT Solutions for Class 11 Physics Chapter 12: Download PDF

Free download of Kinetic Theory of Gases Class 11 Solutions PDF for CBSE exams and strengthen your understanding with step-by-step explanations and solved exercises.

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NCERT Solutions for Class 11 Physics Chapter 12 Kinetic Theory - Exercise Questions

Q12.1 Estimate the fraction of molecular volume to the actual volume occupied by oxygen gas at STP. Take the diameter of an oxygen molecule to be 3 Å.

Answer:

The diameter of an oxygen molecule, d = 3 Å.

The actual volume of a mole of oxygen molecules V actual is

Vactual=NA43π(d2)3
Vactual=6.023×1023×43π×(3×10102)3
Vactual=8.51×106m3
Vactual=8.51×103litres

The volume occupied by a mole of oxygen gas at STP is V molar = 22.4 litres

VactualVmolar=8.51×10322.4

VactualVmolar=3.8×104

Q12.2 Molar volume is the volume occupied by 1 mol of any (ideal) gas at standard temperature and pressure (STP: 1 atmospheric pressure, 00C ). Show that it is 22.4Litres .

Answer:

As per the ideal gas equation

PV=nRTV=nRTP

For one mole of a gas at STP we have

V=1×8.314×2731.013×105
V=0.0224m3

V=22.4 litres

Q12.3 Figure 13.8 shows plot of PV/T versus P for 1.00×103 kg of oxygen gas at two different temperatures.

(a) What does the dotted plot signify?
(b) Which is true: T1>T2orT1<T2 ?
(c) What is the value of PV/T where the curves meet on the y-axis?
(d) If we obtained similar plots for 1.00×103 kg of hydrogen, would we get the same
value of PV/T at the point where the curves meet on the y-axis? If not, what mass
of hydrogen yields the same value of PV/T (for low pressure high temperature
region of the plot) ? (Molecular mass of H2=2.02μ , of O2=32.0μ ,
R=8.31Jmol1K1 .)

Answer:

(a) The dotted plot corresponds to the ideal gas behaviour.

(b) We know the behaviour of a real gas tends close to that of ideal gas as its temperature increases and since the plot corresponding to temperature T 1 is closer to the horizontal line that the one corresponding to T 2 we conclude T 1 is greater than T 2.

(c) As per the ideal gas equation

PVT=nR

The molar mass of oxygen = 32 g

n=132

R = 8.314

nR=132×8.314nR=0.256JK1

(d) If we obtained similar plots for 1.00×103 kg of hydrogen we would not get the same
value of PV/T at the point where the curves meet on the y-axis as 1 g of Hydrogen would contain more moles than 1 g of Oxygen because of having smaller molar mass.

Molar Mass of Hydrogen M = 2 g

mass of hydrogen

m=PVTMR=0.256×28.314=5.48×105Kg

Q12.4 An oxygen cylinder of volume 30 litres has an initial gauge pressure of 15 atm and a temperature of 270C . After some oxygen is withdrawn from the cylinder, the gauge pressure drops to 11 atm and its temperature drops to 170C . Estimate the mass of
oxygen taken out of the cylinder ( R=8.31Jmol1K1 , molecular mass of O2=32μ ).

Answer:

Initial volume, V 1 = Volume of Cylinder = 30 l

Initial Pressure P 1 = 15 atm

Initial Temperature T 1 = 27 o C = 300 K

The initial number of moles n 1 inside the cylinder is

n1=P1V1RT1n1=15×1.013×105×30×1038.314×300n1=18.28

Final volume, V 2 = Volume of Cylinder = 30 l

Final Pressure P 2 = 11 atm

Final Temperature T 2 = 17 o C = 290 K

The final number of moles n 2 inside the cylinder is

n2=P2V2RT2n2=11×1.013×105×30×1038.314×290n2=13.86

Moles of oxygen taken out of the cylinder = n 2 -n 1 = 18.28 - 13.86 = 4.42

Mass of oxygen taken out of the cylinder m is

m=4.42×32m=141.44g

Q12.5 An air bubble of volume 1.0cm3 rises from the bottom of a lake 40m deep at a temperature of 120C . To what volume does it grow when it reaches the surface, which is at a temperature of 350C ?

Answer:

Initial Volume of the bubble, V 1 = 1.0 cm 3

Initial temperature, T 1 = 12 o C = 273 + 12 = 285 K

The density of water is ρw=103 kg m3

Initial Pressure is P 1

Depth of the bottom of the lake = 40 m

P1=Atmospheric Pressure+Pressure due to waterP1=Patm+ρwghP1=1.013×105+103×9.8×40P1=4.93×105Pa

Final Temperature, T 2 = 35 o C = 35 + 273 = 308 K

Final Pressure = Atmospheric Pressure =1.013×105Pa

Let the final volume be V 2

As the number of moles inside the bubble remains constant, we have

P1V1T1=P2V2T2

V2=P1T2V1P2T1

V2=4.93×105×308×11.013×105×285

V2=5.26 cm3

Q12.6 Estimate the total number of air molecules (inclusive of oxygen, nitrogen, water vapour and other constituents) in a room of capacity 25.0m3 at a temperature of 270C and 1atm pressure.

Answer:

The volume of the room, V = 25.0 m 3

Temperature of the room, T = 27 o C = 300 K

The pressure inside the room, P = 1 atm

Let the number of moles of air molecules inside the room be n

n=PVRTn=1.013×105×258.314×300n=1015.35

Avogadro's Number, NA=6.022×1023

The number of molecules inside the room is N

N=nNAN=1015.35×6.022×1023N=6.114×1026

Q12.7 Estimate the average thermal energy of a helium atom at (i) room temperature ( 270C ), (ii) the temperature on the surface of the Sun ( 6000K ), (iii) the temperature of 10 million kelvin (the typical core temperature in the case of a star).

Answer:

The average energy of a Helium atom is given as 3kT2 since it is monoatomic

(i)

E=3kT2

E=3×1.38×1023×3002

E=6.21×1021 J

(ii)

E=3kT2

E=3×1.38×1023×60002

E=1.242×1019 J

(iii)

E=3kT2

E=3×1.38×1023×1072

E=2.07×1016 J

Q12.8 Three vessels of equal capacity have gases at the same temperature and pressure. The first vessel contains neon (monatomic), the second contains chlorine (diatomic), and the third contains uranium hexafluoride (polyatomic). Do the vessels contain an equal number of respective molecules? Is the root mean square speed of molecules the same in the three cases? If not, in which case is v rms the largest?

Answer:

As per Avogadro's Hypothesis, under similar conditions of temperature and pressure, equal volumes of gases contain an equal number of molecules. Since the volume of the vessels is the same and all vessels are kept at the same conditions of pressure and temperature, they would contain an equal number of molecules.

Root mean square velocity is given as

vrms=3kTm

As we can see, vrms is inversely proportional to the square root of the molar mass; the root mean square velocity will be maximum in the case of Neon as its molar mass is the least.

Q12.9 At what temperature is the root mean square speed of an atom in an argon gas cylinder equal to the rms speed of a helium gas atom at 200C ? (atomic mass of Ar=39.9μ , of He=4.0μ ).

Answer:

As we know root mean square velocity is given as vrms=3RTM

Let at temperature T the root mean square speed of an atom in an argon cylinder equal to the rms speed of a helium gas atom at 200C

3R×T39.9=3R×2534T=2523.7 K

Q12.10 Estimate the mean free path and collision frequency of a nitrogen molecule in a cylinder containing nitrogen at 2.0atm and temperature 170C . Take the radius of a nitrogen molecule to be roughly 1.0A . Compare the collision time with the time the
molecule moves freely between two successive collisions (Molecular mass of N2=28.0μ ).

Answer:

Pressure, P = 2atm

Temperature, T = 17 o C

The radius of the Nitrogen molecule, r=1 Å.

The molecular mass of N 2 = 28 u

The molar mass of N 2 = 28 g

From the ideal gas equation

PV=nRT

nV=PRT

The above tells us about the number of moles per unit volume; the number of molecules per unit volume would be given as

n=NAnV=6.022×1023×2×1.013×1058.314×(17+273)

n=5.06×1025

The mean free path λ is given as

λ=12πnd2

λ=12×π×5.06×1025×(2×1×1010)2

λ=1.11×107 m

The root mean square velocity v rms is given as

vrms=3RTM

vrms=3×8.314×29028×103

vrms=508.26 m s1

The time between collisions T is given as

T=1Collision Frequency

T=1ν

T=λvrms

T=1.11×107508.26

T=2.18×1010s

Collision time T' is equal to the average time taken by a molecule to travel a distance equal to its diameter

T=dvrms

T=2×1×1010508.26

T=3.935×1013s

The ratio of the average time between collisions to the collision time is

TT=2.18×10103.935×1013TT=554
Thus, we can see that the time between collisions is much larger than the collision time.

Additional Questions

Q 1) A metre-long narrow bore held horizontally (and closed at one end) contains a 76cm long mercury thread, which traps a 15cm column of air. What happens if the tube is held vertically with the open end at the bottom?

Answer:

Initially, the pressure of the 15 cm long air column is equal to the atmospheric pressure, P 1 = 1 atm = 76 cm of Mercury

Let the crossectional area of the tube be x cm 2

The initial volume of the air column, V 1 = 15x cm 3

Let's assume that once the tube is held vertical, y cm of Mercury flows out of it.

The pressure of the air column after y cm of Mercury has flown out of the column P 2 = 76 - (76 - y) cm of Mercury = y cm of mercury

Final volume of air column V 2 = (24 + y)x cm 3

Since the temperature of the air column does not change

P1V1=P2V276×15x=y×(24+y)x1140=y2+24yy2+24y1140=0

Solving the above quadratic equation, we get y = 23.8 cm or y = -47.8 cm

Since a negative amount of mercury cannot flow out of the column, y cannot be negative. Therefore, y = 23.8 cm.

Length of the air column = y + 24 = 47.8 cm.

Therefore, once the tube is held vertically, 23.8 cm of Mercury flows out of it, and the length of the air column becomes 47.8 cm

Q 2) From a certain apparatus, the diffusion rate of hydrogen has an average value of 28.7cm3s1. The diffusion of another gas under the same conditions is measured to have an average rate of 7.2cm3s1. Identify the gas.

Answer:

As per Graham's Law of diffusion, if two gases of Molar Mass M 1 and M 2 diffuse with rates R 1 and R 2 respectively, their diffusion rates are related by the following equation

R1R2=M2M1

In the given question

R 1 = 28.7 cm 3 s -1

R 2 = 7.2 cm 3 s -1

M 1 = 2 g

M2=M1(R1R2)2M2=2×(28.77.2)2M2=31.78g

The above Molar Mass is close to 32, therefore, the gas is Oxygen.

Q 3) A gas in equilibrium has uniform density and pressure throughout its volume. This is strictly true only if there are no external influences. A gas column under gravity, for example, does not have uniform density (and pressure). As you might expect, its density decreases with height. The precise dependence is given by the so-called law of atmospheres n2=n1exp[mg(h2h1)/kbT]

where n2, n1 refer to number density at heights h2 and h1 respectively. Use this relation to derive the equation for the sedimentation equilibrium of a suspension in a liquid column:

n2=n1exp[mgNA(ρρ)(h2h1)/(ρRT)]
where ρ is the density of the suspended particle, and ρ , that of the surrounding medium. [ NA s Avogadro’s number, and R the universal gas constant.] [Hint: Use Archimedes' principle to find the apparent weight of the suspended particle.]

Answer:

n2=n1exp[mg(h2h1)/kbT] (i)

Let the suspended particles be spherical and have a radius r

The gravitational force acting on the suspended particles would be

FG=43πr3ρg

The buoyant force acting on them would be

FB=43πr3ρg

The net force acting on the particles become

Fnet=FGFBFnet=43πr3ρg43πr3ρgFnet=43πr3g(ρρ)

Replacing mg in equation (i) with the above equation, we get

n2=n1exp[43πr3g(ρρ)(h2h1)/kbT]n2=n1exp[43πr3g(ρρ)(h2h1)RTNA]n2=n1exp[mgNA(ρρ)(h2h1)RTρ]

The above is the equation to be derived

Q 4) Given below are densities of some solids and liquids. Give rough estimates of the size of their atoms :

Substance

Atomic Mass (u)

Density (10 3 Kg m 3 )

Carbon (diamond)

12.01

2.22

Gold

197

19.32

Nitrogen (liquid)

14.01

1

Lithium

6.94

0.53

Fluorine

19

1.14

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Answer:

Let one mole of a substance of atomic radius r and density ρ have molar mass M

Let us assume the atoms to be spherical

Avogadro's number is NA=6.022×1023

NA43πr3ρ=Mr=(3M4NAπρ)13

For Carbon

NA43πr3ρ=Mr=(3×12.014×6.022×1023×π×2.22×103)13r=1.29 Å.

For gold

NA43πr3ρ=Mr=(3×197.004×6.022×1023×π×19.32×103)13r=1.59 Å.

For Nitrogen

NA43πr3ρ=Mr=(3×14.014×6.022×1023×π×1.00×103)13r=1.77 Å.

For Lithium

NA43πr3ρ=Mr=(3×6.944×6.022×1023×π×0.53×103)13r=1.73 Å.

For Fluorine

NA43πr3ρ=Mr=(3×19.004×6.022×1023×π×1.14×103)13r=1.88 Å.

Class 11 Physics Chapter 12 NCERT solutions help students understand how tiny particles in matter behave. This chapter explains gases and their thermal properties, linking to thermodynamics. Studying it helps in exams and builds a strong foundation in physics.

Kinetic Theory Chapter 12 Physics NCERT Solutions: Concepts and Important Formulas

12.1 Introduction

The kinetic theory explains the behaviour of gases by assuming they consist of a large number of tiny particles (atoms or molecules) in constant random motion. This theory helps derive gas laws and explain properties like pressure, temperature, and specific heat.


12.2 Molecular Nature of Matter

  • Matter is made up of tiny molecules that are in continuous motion.
  • The molecular interactions vary in solids, liquids, and gases.
  • Gases have negligible interatomic forces, allowing them to expand and fill any container.

12.3 Behavior of Gases

  • Gases obey different laws like Boyle's Law and Charles's Law at low pressure and high temperature.
  • The Ideal Gas Equation is given by:

PV=nRT

where P= pressure, V= volume, n= number of moles, R= universal gas constant, T= temperature (Kelvin).


12.4 Kinetic Theory of an Ideal Gas

  • Gas molecules move in random directions, colliding elastically with each other and with the walls of the container.
  • Pressure of an Ideal Gas:

P=13ρvrms2

where ρ= density of gas, vamxam= root mean square velocity of gas molecules.

  • Root Mean Square Speed ( vmas ):

vrms=3kTm

where k= Boltzmann constant, T= absolute temperature, m= mass of a gas molecule.

12.5 Law of Equipartition of Energy

  • Energy is equally distributed among all degrees of freedom in thermal equilibrium.
  • Energy per molecule in an ideal gas:

E=f2kT

where f= degrees of freedom.


12.6 Specific Heat Capacity

  • Monoatomic gas: Cv=32R,Cp=52R
  • Diatomic gas: Cv=52R,Cp=72R
  • Relation between Cp and Cv :

CpCv=R

12.7 Mean Free Path

  • The mean free path (λ) is the average distance a molecule travels before colliding with another molecule.

λ=kT2πd2P

where d= diameter of the gas molecule, P= pressure .

Importance of NCERT Solutions for Class 11 Physics Chapter 12 – Kinetic Theory

  • Helps in understanding key concepts and equations in the chapter.
  • Useful for class exams and competitive exams like NEET & JEE Mains (1 question is usually asked).
  • Covers important formulas, making problem-solving easier.
  • This chapter holds 2-3% weightage in competitive exams, so mastering it is beneficial.

Kinetic Theory Class 11 Physics NCERT Topics

SectionTopic Name
12.1Introduction
12.2Molecular nature of matter
12.3Behaviour of gases
12.4Kinetic theory of an ideal gas
12.5Law of equipartition of energy
12.6Specific heat capacity
12.7Mean free path

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NCERT Solutions of Thermodynamics Physics 11: Important Formulas

  • Thermodynamics First Law

ΔQ=ΔU+ΔW

Where:

ΔQ is heat provided to the system by the environment, ΔW denotes the amount of work done by the system in relation to the environment, and ΔU is the change in the system's internal energy

  • Thermodynamics Second Law

ds >= 0

Where: S is entropy

  • Thermodynamics Third Law

S →0 as T →0

Where: s is entropy and T is the temperature

  • Molar Specific Heat Capacity

C=S/μ=ΔQ/μΔT

Here: μ= the mass of material in moles, C is the substance's molar specific heat capacity, ΔQ is the quantity of heat that a substance absorbs or rejects, and ΔT stands for temperature change.

These thermodynamics physics class 11 formulas are valuable tools that students can utilize to calculate and analyze various thermodynamic parameters, making it easier to solve complex problems and gain a deeper understanding of heat, energy, and the laws of thermodynamics.

Importance of NCERT Solutions for Class 11 Physics Chapter 11 Thermodynamics

  • As the Class 11 exams and competitive exams like NEET and JEE Main are considered, the NCERT solutions for Class 11 are important.
  • At least one question is expected for JEE Mains, and two questions are expected for NEET from the chapter on Thermodynamics.

How to Solve Class 11 Physics Chapter 11 NCERT Questions

  • Read the question carefully and list the given values (P, V, T, Q, W, U).
  • Identify the type of process (Isothermal, Adiabatic, Isobaric, Isochoric or Cyclic).
  • Use the First Law of Thermodynamics to relate Heat, Work, and Energy.
  • Learn Important Formulas
  • Practice with Example Problems
  • Check your units and dimensions in every answer

NCERT Solutions for Class 11 Subject wise

Also, check NCERT Books and NCERT Syllabus here

Subject wise NCERT Exemplar solutions

If you have any queries or uncertainties that are not addressed in the class 11 physics chapter 11 exercise solutions or any other chapter, you can contact us. You will get answers to your questions, which can aid you in achieving better scores in your exams.

Frequently Asked Questions (FAQs)

1. What is the weightage of Thermodynamics for JEE Main

One question from Class 11 chapter Thermodynamics is expected for JEE Main. Students should practice previous year papers of JEE Main to get a good score.

2. What is the weightage of thermodynamics for NEET

Two questions from class 11 chapter Thermodynamics is expected for NEET. The competition level of NEET exam is very high. So practicing more questions is important. To practice more questions refer to NCERT exemplar and NEET previous year papers

3. Is Thermodynamics helpful in higher studies

Yes, the concepts of thermodynamics are used in various fields of Engineering and Science. Not only Thermodynamics chapter, all the chapters in NCERT book are basics of some field of higher studies.

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A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg

 

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

Option 2)

\; K\;

Option 3)

zero\;

Option 4)

K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

Option 4)

be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)

Molality

Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

Option 4)

Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

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