Degrees of Freedom and Kinetic Theory of Gases

Comprehensive quiz covering degrees of freedom, law of equipartition of energy, kinetic theory of gases, heat capacities, and thermodynamic processes for Class XI physics

59 Questions Published

Questions

Question 1 Multiple Choice (Single Answer)

How many degrees of freedom the gas molecules have if under STP the gas density $\rho = 1.3 kg/m^3$ and the velocity of sound propagation in it is $330 ms^{-1}$?

  1. $3$
  2. $5$
  3. $7$
  4. $8$
Question 2 Multiple Choice (Single Answer)

At room temperature (27$^0$ C) the rms speed of the moleculesof certain diatomic gas is found to be 1920 ms$^{-1}$ then the molecule is:

  1. $H _2$
  2. $F _2$
  3. $O _2$
  4. $Cl _2$
Question 3 Multiple Choice (Single Answer)

If temperature of body increases by 10%, then increase in radiated energy of the body is :

  1. 10 %
  2. 40 %
  3. 46 %
  4. 1000 %
Question 4 Multiple Choice (Single Answer)

The law of equipartition of energy was given by :

  1. Claussius
  2. Maxwell
  3. Boltzmann
  4. Carnot
Question 5 Multiple Choice (Single Answer)

The value of $\gamma$ for gas X is 1.66, then x is :

  1. Ne
  2. O$ _3$
  3. N$ _2$
  4. H$ _2$
Question 6 Multiple Choice (Single Answer)

An ant is moving on a plane horizontal surface. The number of degrees of freedom of the ant will be

  1. 1
  2. 2
  3. 3
  4. 6
Question 7 Multiple Choice (Single Answer)

Gas exerts pressure on the walls of container because the molecules-

  1. Are loosing the kinetic energy
  2. Are getting stuck to the walls
  3. Are transferring their momentum to walls
  4. Are accelerated toward walls.
Question 8 Multiple Choice (Single Answer)

A man is climbing up a spiral type staircase. His degrees of freedom are :

  1. 1
  2. 2
  3. 3
  4. more than 3
Question 9 Multiple Choice (Single Answer)

A system consists of N particles, which have independent K relations among one another. The number of degrees of freedom of the system is given by :

  1. 3 NK
  2. N/3K
  3. 3 N/K
  4. 3N - K
Question 10 Multiple Choice (Single Answer)

The correct relation connecting the universal gas constant (R), Avogadro number N$ _A$ and Boltzmann constant (K) is :

  1. $R = NK^2$
  2. $K = NR$
  3. $N = RK$
  4. $R=NK$
Question 11 Multiple Choice (Single Answer)

A circular disc of mass $m$ and radius $r$ is rolling about its axis with a constant speed $v$. Its kinetic energy is 

  1. $\cfrac{1}{4}mv^2$
  2. $\cfrac{1}{2}mv^2$
  3. $\cfrac{3}{4}mv^2$
  4. $mv^2$
Question 12 Multiple Choice (Single Answer)

The number of degrees of freedom for each atom of a monoatomic gas is :

  1. 3
  2. 5
  3. 6
  4. 1
Question 13 Multiple Choice (Single Answer)

The internal energy of a gas:

  1. is the sum total of kinetic and potential energies.
  2. is the total transitional kinetic energies
  3. is the total kinetic energy of randomly moving molecules.
  4. is the total kinetic energy of gas molecules
Question 14 Multiple Choice (Single Answer)

State whether true or false:

Linear molecules have $3N-5$ vibrational degrees of freedom, whereas non linear molecules have $3N-6$ vibrational degrees of freedom, where N is no. of atoms present in a molecule.

  1. True
  2. False
Question 15 Multiple Choice (Single Answer)

The number of degrees of freedom in an oxygen molecule is 

  1. 3
  2. 4
  3. 5
  4. 6
Question 16 Multiple Choice (Single Answer)

Significant motion for the molecules of a monoatomic gas corresponds to :

  1. translatory
  2. vibratory
  3. rotatory
  4. none of these
Question 17 Multiple Choice (Single Answer)

To find out degree of freedom, the correct expression is :

  1. $f=\dfrac { 2 }{ \gamma -1 }$
  2. $f=\dfrac { \gamma +1 }{ 2 }$
  3. $f=\dfrac { 2 }{ \gamma +1 }$
  4. $f=\dfrac { 1 }{ \gamma +1 }$
Question 18 Multiple Choice (Single Answer)

The total Kinetic energy of $1\ mole$ of ${N}^{} _{2}$ at $27^{o} _{}{C}$ will be approximately :-

  1. $1500\ J$
  2. $15633\ cal$
  3. $1500\ kcal$
  4. $1500\ erg$
Question 19 Multiple Choice (Single Answer)

An ideal gas having initial pressure P, volume V and temperature T is allowed to expand adiabatically until its volume becomes $5.66$V while its temperature falls to $T/2$. How many degrees of freedom do the gas molecules have?

  1. 7
  2. $5$.
  3. 6
  4. 8
Question 20 Multiple Choice (Single Answer)

The total kinetic energy of $1$ mole of $N _2$ at $27$C will be approximately

  1. <span><span><span class="mrow"><span class="mn">3739.662 J</span></span></span></span>&nbsp;
  2. 1500 calorie
  3. 1500 kilo calorie
  4. 1500 erg.
Question 21 Multiple Choice (Single Answer)

Three particles are situated on a light and rigid rod along Y-axis as shown in the figure. If the system is rotating with angular velocity of $2 rad/sec$ about X axis, then the total kinetic energy of the system is :

  1. $92 J $
  2. $184 J $
  3. $ 276 J $
  4. $46 J $
Question 22 Multiple Choice (Single Answer)

A gas has molar heat capacity $C = 4.5\ R$ in the process $PT = constant$. Find the number of degrees of freedom (n) of molecules in the gas.

  1. $n = 7$
  2. $n = 3$
  3. $n = 5$
  4. $n = 2$
Question 23 Multiple Choice (Single Answer)

A gas undergoes a process such that $P \alpha \dfrac{1}{T}$. If the molar heat capacity for this process is $24.93 ,J/mol ,K$, then what is the degree of freedom of the molecules of the gas?

  1. $8$
  2. $4$
  3. $2$
  4. $6$
Question 24 Multiple Choice (Single Answer)

The degrees of freedom of a triatomic gas is? (consider moderate temperature)

  1. $6$
  2. $4$
  3. $2$
  4. $8$
Question 25 Multiple Choice (Single Answer)

A vessel contains a non-linear triatomic gas. If $50$% of gas dissociate into individual atom, then find new value of degree of freedom by ignoring the vibrational mode and any further dissociation 

  1. $2.15$
  2. $3.75$
  3. $5.25$
  4. $6.35$
Question 26 Multiple Choice (Single Answer)

For gas, if the ratio of specific heats at constants pressure $P$ and constant volume $V$ is $\gamma $, then the value of degree of freedom is:

  1. $\dfrac{\gamma +1}{\gamma -1}$
  2. $\dfrac{\gamma -1}{\gamma +1}$
  3. $\dfrac{1}{2}(\gamma-1)$
  4. $\dfrac{2}{\gamma-1}$
Question 27 Multiple Choice (Single Answer)

The speed of a longitudinal wave in a mixture containing 4 moles of He and 1 mole of Ne at 300 K will be

  1. 930 m/s
  2. 541 m/s
  3. 498 m/s
  4. None of these
Question 28 Multiple Choice (Single Answer)

$2$ grams of mono atomic gas occupies a volume of $2$ litres at a pressure of $8.3 \times 10^5$ Pa and $127^0C$. Find the molecular weight of the gas.

  1. $2$ grams/mole
  2. $16$ grams/mole
  3. $4$ grams/mole
  4. $32$ grams/mole
Question 29 Multiple Choice (Single Answer)

A vessel contains a non-linear triatomic gas. If $50$% of gas dissociate into individual atom, then find new value of degree of freedom by ignoring the vibrational mode and any further dissociation.

  1. 2.15
  2. 3.75
  3. 5.25
  4. 6.35
Question 30 Multiple Choice (Single Answer)

When an ideal monoatomic  gas is heated zt constant pressure , which of the following may be true

  1. $\dfrac {dU}{dQ} = \frac {3}{5}$
  2. $\dfrac {dW}{dQ} = \frac {2]}{5}$
  3. $\dfrac {dU}{dQ} = \frac {4}{5}$
  4. $dW + dU = dQ $
Question 31 Multiple Choice (Single Answer)

If $\gamma $ be the ration of specific heats of a perfect gas, the number of degree of freedom of a molecule of the gas is:

  1. $\dfrac{{25}}{2}\left( {\gamma - 1} \right)$
  2. $\dfrac{{3\gamma - 1}}{{2\gamma - 1}}$
  3. $\dfrac{2}{{\gamma - 1}}$
  4. $\dfrac{9}{2}(\gamma - 1)$
Question 32 Multiple Choice (Single Answer)

The degree of freedom of a diatomic gas at normal temperature is.

  1. $7$
  2. $6$
  3. $5$
  4. $4$
Question 33 Multiple Choice (Single Answer)

On increasing temperature of the reacting system by $10$ degrees the rate of reaction almost doubles. The most appropriate reason for this is

  1. collision frequency increases
  2. activation energy decreases by increases in temperatuer
  3. the fraction of molecules having energy equal to threshold energy or more increase
  4. the value of threshold energy decreases
Question 34 Multiple Choice (Single Answer)

An ant is walking on the horizontal surface. The number of degree of freedom of ant will be

  1. $1$
  2. $2$
  3. $3$
  4. $6$
Question 35 Multiple Choice (Single Answer)

n moles of an ideal monoatomic gas undergoes an isothermal expansion at temperature T during which its volume becomes 4 times. The work done on the gas and change in internal energy of the gas respectively is

  1. n RT Ln 4,0
  2. - n RT Ln 4,0
  3. n RT Ln 4 $\frac { 3 n R T } { 2 }$
  4. - n RT Ln 4, $\frac { 3 n R T } { 2 }$
Question 36 Multiple Choice (Single Answer)

A mixture Of $n _ { 2 }$ moles of mono atomic gas and $n _ { 2 }$ moles of diatomic gas has $\frac { C _ { p } } { C _ { V } } = y = 1.5$

  1. $n _ { 1 } = n _ { 2 }$
  2. $2 n _ { 1 } = n _ { 2 }$
  3. $n _ { 1 } = 2 n _ { 2 }$
  4. $2 n _ { 1 } = 3 n _ { 2 }$
Question 37 Multiple Choice (Single Answer)

70 calorie of heat required to rise the temperature of 2 mole of an ideal gas at constant pressure from ${30^o}$C to ${35^o}$C. The degrees of freedom of the gas molecule are,,

  1. 3
  2. 5
  3. 6
  4. 7
Question 38 Multiple Choice (Single Answer)

Three perfect gases at absolute temperatures $T _1, T _2$ and $T _3$ are mixed. The masses of their molecules are $m _1, m _2$ and $m _3$ and the number of molecules are $n _1, n _2$ and $n _3$ respectively. Assuming no loss of energy, the final tempreture of the mixture is 

  1. $\dfrac{T _1 + T _2 + T _3}{3}$
  2. $\dfrac{n _1T _1 + n _2T _2 + T _3 T _3}{n _1 + n _2 + n _3}$
  3. $\dfrac{n _1T _1^2 + n _2T _2^2 + n _3 T _3^2}{n _1 T _1 + n _2 T _2 + n _3 T _3}$
  4. $\dfrac{n _1^2T _1^2 + n _2^2T _2^2 + n _3^2 T _3^2}{n _1 T _1 + n _2 T _2 + n _3 T _3}$
Question 39 Multiple Choice (Single Answer)

The law of equipartition of energy is applicable to the system whose constituents are :

  1. in random motion
  2. in orderly motion
  3. at rest
  4. moving with constant speed
Question 40 Multiple Choice (Single Answer)

The heat capacity at constant volume of a sampleof 192 g of gas in a container of volume 80$\mathrm { L }$ at atemperature of $402 ^ { \circ } \mathrm { C }$ and at a pressure of$4.2 \times 10 ^ { 5 } \mathrm { Pa }$ is 124.5$\mathrm { JK }$ . The number of thedegrees of freedom of the gas molecules is 

  1. 3
  2. 5
  3. 7
  4. 6
Question 41 Multiple Choice (Single Answer)

The kinetic energy associated with per degree of freedom of a molecule is

  1. $\dfrac { 1 }{ 2 } M^{ 2 } _{ rms }$
  2. $kT$
  3. $kT/2$
  4. $3 kT/2$
Question 42 Multiple Choice (Single Answer)

Statement -1 : The total translational kinetic energy of all the molecules of a given mass of an ideal gas is 1.5 times the product of its pressure and its volume.
and
Statement -2: The molecules of a gas collide with each other and the velocities of the molecules change due to the collision.

  1. Statement - 1 is True, Statement -2 is True, Statement -2 is a correct explanation for Statements-1
  2. Statement - 1 is True, Statement -2 is True, Statement -2 is NOT a correct explanation for Statements-1
  3. Statement - 1 is True, Statement -2 is False
  4. Statement - 1 is False, Statement -2 is True
Question 43 Multiple Choice (Single Answer)

In a process $PT=Constant$, if molar heat capacity of a gas is $C=37.35J/mol=K$, then find the number of degrees of freedom of molecules in the gas.

  1. $n=10$
  2. $n=5$
  3. $n=6$
  4. $n=7$
Question 44 Multiple Choice (Single Answer)

The degree of freedom per molecule of a gas is $3$. The heat absorbed by the gas at constant pressure is $150,J$. Then increase in internal energy is 

  1. $90,J$
  2. $50,J$
  3. $120,J$
  4. $30,J$
Question 45 Multiple Choice (Single Answer)

How many degrees of freedom are associated with 2grams of He at NTP?

  1. 3
  2. $3.01\times10^{23}$
  3. $9.03\times10^{23}$
  4. 6
Question 46 Multiple Choice (Single Answer)

At ordinary temperatures, the molecules of a diatomic gas have only translational and rotational kinetic energies. At high temperatures, they may also have vibrational energy. As a result of this compared to lower temperatures, a diatomic gas at higher temperatures will have-

  1. lower molar heat capacity
  2. higher molar heat capacity
  3. lower isothermal compressibility
  4. higher isothermal compressibility
Question 47 Multiple Choice (Single Answer)

When the temperature is increased from 0$^o$C to 273$^o$C, in what ratio the average kinetic energy of molecules changes?

  1. 1
  2. 5
  3. 4
  4. 2
Question 48 Multiple Choice (Single Answer)

When x amount of heat is given to a gas at constant pressure, it performs $\displaystyle \frac{x}{3}$ amount of work. The average number of degrees of freedom per molecule of the gas is-

  1. 3
  2. 4
  3. 5
  4. 6
Question 49 Multiple Choice (Single Answer)

The mean kinetic energy of a gas molecule is proportional to 

  1. $\displaystyle \sqrt { T } $
  2. $\displaystyle { T }^{ 3 }$
  3. $\displaystyle T$
  4. None of the above
Question 50 Multiple Choice (Single Answer)

The degrees of freedom of a diatomic gas at normal temperature is

  1. 3
  2. 4
  3. 5
  4. 6
Question 51 Multiple Choice (Single Answer)

The number of vibrational degrees of freedom for a $CO _2$ molecule is

  1. 4
  2. 5
  3. 6
  4. 9
Question 52 Multiple Choice (Single Answer)

For polyatomic molecules having 'f' vibrational modes, the ratio of two specific heats, $\dfrac{C _p}{C _v}$ is ............

  1. $\dfrac{1+f}{2+f}$
  2. $\dfrac{2+f}{3+f}$
  3. $\dfrac{4+f}{3+f}$
  4. $\dfrac{5+f}{4+f}$
Question 53 Multiple Choice (Single Answer)

If for a gas $\dfrac{R}{C _V}=0.67$, this gas is made up of molecules which are.

  1. Monatomic
  2. Diatomic
  3. Polyatomic
  4. Mixture of diatomic and polyatomic molecules
Question 54 Multiple Choice (Single Answer)

The average degree of freedom per molecule for a gas is 6. The gas performs 25 J of work when it expands at constant pressure. The heat absorbed by the gas is

  1. 75 J
  2. 100 J
  3. 150 J
  4. 125 J
Question 55 Multiple Choice (Single Answer)

A gas performs Q work when it expand at constant pressure. During this process heat absorbed by the gas is 4Q. The average number of degrees of freedom for the gas is:

  1. 5
  2. 6
  3. 4
  4. 3.5
Question 56 Multiple Choice (Single Answer)

N moles of an ideal diatomic gas is contained in a cylinder at temperature $T.$ On supplying some heat to cylinder, $N/3$ moles of gas disassociated into atoms while temperature remains constant. Heat supplied to the gas is

  1. $\dfrac {NRT}{3}$
  2. $\dfrac {5NRT}{2}$
  3. $\dfrac {8NRT}{3}$
  4. $\dfrac {NRT}{6}$
Question 57 Multiple Choice (Single Answer)

The heat capacity at constant volume of a sample of a monoatomic gas is $35\ J/K$. Find the number of moles.

  1. $12.81 \ \ mol &nbsp;$
  2. <span>$21.81 \ \ mol &nbsp;$</span>
  3. <span>$4.81 \ \ mol &nbsp;$</span>
  4. <span>$2.81 \ \ mol &nbsp;$</span>
Question 58 Multiple Choice (Single Answer)

Relation between pressure ($P$) and energy density ($E$) of an ideal gas is-

  1. $P=2/3E$
  2. $P=3/2E$
  3. $P=3/5E$
  4. $P=E$
Question 59 Multiple Choice (Single Answer)

A vessel of volume $0.3 \ { { m }^{ 3 } }$ contains Helium at $20.0$. The average kinetic energy per molecule for the gas is:

  1. $6.07\times { 10 }^{ -21 }J$
  2. $7.3\times { 10 }^{ 3 }J$
  3. $14.6\times { 10 }^{ 3 }J$
  4. $12.14\times { 10 }^{ -21 }J$