CBSE Questions for Class 11 Engineering Physics Kinetic Theory Quiz 5 - MCQExams.com

A uniform tube with piston in the middle and containing a gas at 0$$^{0}$$C is heated to 100$$^{0}$$C at one side . If the piston moves 5 cm, find the length of the tube containing the gas at 100$$^{0}$$C.
  • 16.75 cm
  • 37.5 cm
  • 28.25 cm
  • 12.5 cm

In a given species of tobbaco there is 0.1 mg of virus per c.c. The mass of virus is $$4 \times 10^{7}$$ Kg per kilomol. The number of the molecules of virus present in 1 c.c. will be
  • $$10^{13}$$
  • $$10^{11}$$
  • $$1.5 \times 10^{12}$$
  • $$10^{14}$$

A vertical cylindrical vessel separated in two parts by a frictionless piston free to move along the length of a vessel. The length of vessel is 90 cm and the piston divides the cylinder in the ratio 2 :Each of the two parts contain 0.1 mole of an ideal gas. The temperature of the gas is $$27^{o}$$C in each part. The mass of the piston is
  • 41.5 kg
  • 8.97 kg
  • 9.57 kg
  • 11.57 kg

At what temperature the linear kinetic energy of a gas molecule will be equal to that of an electron accelerated through a potential difference of 10 volt?
  • 77.3 x 10$$^{3}$$ K
  • 38.65 x 10$$^{3}$$ K
  • 19.x10$$^{3}$$ K
  • 273 K
One gram mol of helium at 27$$^{0}$$ C is mixed with three gram mols of oxygen at 127$$^{0}$$ C at constant pressure. If there is no exchange of heat with the atmosphere then the final temperature will be
  • 375 K
  • 175K
  • 475 K
  • 575K

The mean molecular energy of gas at 300 K will be
  • 6.2 x 10$$^{20}$$ Joule
  • 6.2 x 10$$^{-20}$$Joule
  • 6.2 x 10$$^{-21}$$Joule
  • 2.6 x 10$$^{-20}$$Joule

The degrees of freedom of a diatomic gas at normal temperature is
  • 3
  • 4
  • 5
  • 6

Equal masses of $$N_{2}$$ and $$O_{2}$$ gases are filled in vessel A and B. The volume of vessel B is double of A. The ratio of pressure in vessel A and B will be
  • 16:7
  • 16:14
  • 32:7
  • 32:28

A partially inflated balloon contains 500 m$$^{3}$$ of helium at 27$$^{0}$$ C and 1 atm pressure. The volume of the helium at an altitude of 6000 m, where the pressure is 0.5atm and the temperature is -3$$^{0}$$C is
  • 22.4 lit
  • 11.2 lit
  • 900 m$$^{3}$$
  • 50 m$$^{3}$$
The temperature of gas is increased from 27$$^{o}$$C to 127$$^{o}$$C. The ratio of its mean kinetic energies will be
  • $$\dfrac{3}{4}$$
  • $$\dfrac{4}{3}$$
  • $$\dfrac{9}{16}$$
  • $$\dfrac{16}{9}$$

Figure shows a cylindrical tube of cross-sectional area A filled with two frictionless pistons. The pistons are connected through wire. The tension in the wire if the temperature rises from T$$_{0}$$ to 2T$$_{0}$$ is (Initial pressure is P$$_{0}$$, atmospheric pressure)


25690.PNG
  • $$P_{0}A$$
  • $$\frac{P_{0}A}{2}$$
  • $$2P_{0}A$$
  • $$\frac{2P_{0}A}{3}$$

28gm of $$N_2$$ gas is contained in a flask at a pressure of 10atm and at a temperature of 57$$^{0}$$C. It is found that due to leakage in the flask, the pressure is reduced to half and the temperature reduced to 27$$^{0}$$C. The quantity of N$$_{2}$$ gas that leaked out is
  • $$\frac{5}{63}gm$$
  • $$\frac{63}{5}gm$$
  • $$\frac{11}{20}gm$$
  • $$\frac{20}{11}gm$$

$$Assertion$$: gases are characterised with two coefficients of expansion

$$Reason$$: when heated both volume and pressure increase with the rise in temperature


25707.PNG
  • Both assertion (A) and reason (R) are correct and R gives the correct explanation
  • Both assertion (A) and reason (R) are correct but R doesnt give the correct explanation
  • A is true but R is false
  • A is false but R is true

Assertion: Gasses obey Boyle's law at high temperature and low pressure only.

Reason: At low pressure and high temperature, gasses would behave like ideal gases.
  • Both assertion (A) and reason (R) are correct and R gives the correct explanation
  • Both assertion (A) and reason (R) are correct but R does give the correct explanation
  • A is true but R is false
  • A is false but R is true

Follwing operation are carried out on a sample of ideal gas initially at pressure P volume V and kelvin temperature T.

a) At constant volume, the pressure is increased fourfold.

b) At constant pressure, the volume is doubled

c) The volume is doubled and pressure halved.

d) If heated in a vessel open to atmosphere, one-fourth of the gas escapes from the vessel.

Arrange the above operations in the increasing order of final temperature.
  • a,b,c,d
  • c,b,a,d
  • b,a,d,c
  • c,d,b,a

PV = n RT holds good for :

a) Isobaric process          b) Isochoric process

c) Isothermal process     d) Adiabatic process
  • a & b
  • a,b & c
  • a,b & d
  • all

Assertion: In Joules bulb apparatus, as reservoir is moved up, the mercury level raises into the bulb. 

Reason: The pressure on the enclosed gas increases.
  • Both assertion (A) and reason (R) are correct and R gives the correct explanation
  • Both assertion (A) and reason (R) are correct but R doesnt give the correct explanation
  • A is true but R is false
  • A is false but R is true

Assertion:With increase in temperature, the pressure of given gas increases

Reason:Increase in temperature causes decrease in no. of collision of molecules with walls of container.
  • Both assertion (A) and reason (R) are correct and R gives the correct explanation
  • Both assertion (A) and reason (R) are correct but R doesnt give the correct explanation
  • A is true but R is false
  • A is false but R is true

According to kinetic theory of gasses at Zero kelvin

a) Pressure of ideal gas is zero

b) Volume of ideal gas is zero

c) Internal energy of ideal gas is zero

d) Matter exists in gaseous state only
  • a & d are true
  • a,b & d are true
  • a,b & c are true
  • All are true

Which of the following processes will quadruple the pressure

a) Reduce V to half and double T

b) Reduce V to 1/8th and reduce T to half

c) Double V and half T

d) Increase both V and T to double the values
  • b,c
  • a,b
  • c,d
  • a,d.

Assertion:PV/T=constant for 1 mole of gas. This constant is same for all gases.

Reason:1 mole of different gases at NTP occupy same volume of 22.4 litres.
  • Both assertion (A) and reason (R) are correct and R gives the correct explanation
  • Both assertion (A) and reason (R) are correct but R doesnt give the correct explanation
  • A is true but R is false
  • A is false but R is true

Assertion: PV/T=constant for 1 gram of gas. This constant varies from gas to gas.

Reason:1 gram of different gases at NTP occupy different volumes. 
  • Both assertion (A) and reason (R) are correct and R gives the correct explanation
  • Both assertion (A) and reason (R) are correct but R doesnt give the correct explanation
  • A is true but R is false
  • A is false but R is true
To find out degree of freedom, the correct expression is :
  • $$f=\dfrac { 2 }{ \gamma -1 }$$
  • $$f=\dfrac { \gamma +1 }{ 2 }$$
  • $$f=\dfrac { 2 }{ \gamma +1 }$$
  • $$f=\dfrac { 1 }{ \gamma +1 }$$
A vessel contains air and saturated vapor. The pressure of air is $$\mathrm{p}_{2}$$ and $$\mathrm{p}_{1}$$ is the S.V. P. On compressing the mixture to one-fourth of its original volume, what is the increase in pressure of the mixture?
  • $$2\mathrm{p}_{1}$$
  • $$2\mathrm{p}_{2}$$
  • $$3\mathrm{p}_{1}$$
  • $$3\mathrm{p}_{2}$$

Match List I with List II

List-I                                               List-II

a) 0.00366/$$^{0}$$ C                   e) Avagadros Number

b) 6.023x10$$^{23}$$ molecules   f) Universal gas constant

c) -273$$^{0}$$ C                         g) Pressure coefficient of gas

d) 8.31 J/K-mole               h) Intercept of V-T graph at

                                                  constnat pressure
  • a-g, b-e, c-h, d-f.
  • a-f, b-g c-e,d-h.
  • a-g,b-e,c-f, d-h.
  • a-g,b-f, c-e, d-h.
Three perfect gases at absolute temperatures $$\mathrm{T}_{1},\ \mathrm{T}_{2}$$ and $$\mathrm{T}_{3}$$ are mixed. The masses of molecules are $$\mathrm{m}_{1},\ \mathrm{m}_{2}$$ and $$\mathrm{m}_{3}$$ and the number of molecules are $$\mathrm{n}_{1},\ \mathrm{n}_{2}$$ and $$\mathrm{n}_{3}$$ respectively. Assuming no loss of energy, the final temperature of the mixture is:
  • $$\displaystyle \frac{(\mathrm{T}_{1}+\mathrm{T}_{2}+\mathrm{T}_{3})}{3}$$
  • $$\displaystyle \frac{\mathrm{n}_{1}\mathrm{T}_{\mathrm{l}}+\mathrm{n}_{2}\mathrm{T}_{2}+\mathrm{n}_{3}\mathrm{T}_{3}}{\mathrm{n}_{1}+\mathrm{n}_{2}+\mathrm{n}_{3}}$$
  • $$\displaystyle \frac{\mathrm{n}_{1}\mathrm{T}_{1}^{2}+\mathrm{n}_{2}\mathrm{T}_{2}^{2}+\mathrm{n}_{3}\mathrm{T}_{3}^{3}}{\mathrm{n}_{1}\mathrm{T}_{1}+\mathrm{n}_{2}\mathrm{T}_{2}+\mathrm{n}_{3}\mathrm{T}_{3}}$$
  • $$\displaystyle \frac{\mathrm{n}_{1}^{2}\mathrm{T}_{1}^{2}+\mathrm{n}_{2}^{2}\mathrm{T}_{2}^{2}+\mathrm{n}_{3}\mathrm{T}_{3}^{3}}{\mathrm{n}_{1}\mathrm{T}_{1}+\mathrm{n}_{2}\mathrm{T}_{2}+\mathrm{n}_{3}\mathrm{T}_{3}}$$
One $$kg$$ of a diatomic gas is at a pressure of $$ 8\times 10^{4}\ \mathrm{N}/\mathrm{m}^{2}$$. The density of the gas is $$4$$ $$\mathrm{k}\mathrm{g}/\mathrm{m}^{3}$$. What is the energy of the gas due to its thermal motion ? 
  • $$3\times 10^{4}\mathrm{J}$$
  • $$5\times 10^{4}\mathrm{J}$$
  • $$6\times 10^{4}\mathrm{J}$$
  • $$7\times 10^{4}\mathrm{J}$$

Match List I and List II

List-I                                  List-II

a) P-V graph(T is constant)                            e) St. line cutting temp axis at - 273$$^{0}$$            

b) P-T graph(V is constant)                            f) Rectangular hyperbola

c) V-T graph(pressure P is constant)             g) A st.line parallel to axis

d) PV- P garph                                               h) St. line passing trhough origin (T is constant)
  • a-g,b-e,c-h, d-f.
  • a-h, b-f c-g, d-e.
  • a-e, b-g,c-f, d-h.
  • a-f, b-h, c-e,d-g.
The amount of heat energy required to raise the temperature of $$1\ g$$ of Helium at NTP, from $$T_1K$$ to $$T_2K$$ is -
  • $$\displaystyle \dfrac{3}{2}N_a k_B (T_2 - T_1)$$
  • $$\displaystyle \dfrac{3}{4}N_a k_B (T_2 - T_1)$$
  • $$\displaystyle \frac{3}{4}N_a k_B (\frac{T_2}{T_1})$$
  • $$\displaystyle \frac{3}{8}N_a k_B (T_2 - T_1)$$
One mole each of monatomic, diatomic and triatomic ideal gases (kept in three different containers) whose initial volume and pressure are same, each is compressed till their pressure becomes twice the initial pressure. Then which of the following statements is/are incorrect?
  • If the compression is isothermal then their final volumes will be same
  • If the compression is adiabatic, then final volume will be different
  • If the compression is adiabatic, then triatomic gas will have maximum final volume
  • If the compression is adiabatic, then monoatomic gas will have maximum final volume
Producers gas is a mixture of
  • Carbon monoxide and nitrogen gas
  • Carbon monoxide and hydrogen gas
  • Carbon monoxide and water vapour
  • Carbon monoxide and nitrous oxide
Atom of an element is electrically
  • Positive
  • Negative
  • Neutral
  • None of these
An ideal gas can be expanded from an initial state to a certain volume through two different processes (i) $$PV^2 = constant\:and\:(ii)P = KV^2$$ where K is a positive constant. Based on the given situation, choose the correct statements
  • Final temperature in (ii) will be greater than in (i)
  • Final temperature in (ii) will be less than in (i)
  • Total heat given to the gas in case (ii) is greater than in (i)
  • Total heat given to the gas in case (ii) is less than in (i)
K.E. of molecular motion appears as:
  • Pressure
  • P.E.
  • Temperature
  • All of the above
At change of state the kinetic energy of the molecules of a substances increases greatly.
  • True
  • False
  • Either
  • Neither
At pressure P and absolute temperature T a mass M of an ideal gas fills a closed container of volume V. An additional mass 2M of the same gas is added into the container and the volume is then reduced to $$\dfrac{v}{3}$$ and the temperature to $$\dfrac{T}{3}.$$ The pressure of the gas will now be :
  • $$\dfrac{P}{3}$$
  • $$P$$
  • $$3 P$$
  • $$9 P$$
A diatomic gas is filled inside a conducting cylinder. Now we push the piston slowly to make volume of gas half of initial. Pick correct statements
75963.png
  • Pressure of gas Increases because there is more average change in linear momentum of molecule in each collision
  • Pressure force on side wall of container increased
  • Pressure force on piston is increased
  • More molecules collide with piston per unit time
A rigid container has a hole in its wall. When the container is evacuated, its weight is 100 gm. When someair is filled in it at 27C, its weight becomes 200 gm. Now the temperature of air inside is increased by $$\Delta$$ T, the weight becomes 150 gm. $$\Delta$$ T should be :
  • $$27^{\circ}$$
  • $$\dfrac{27^{\circ}} {4}$$ C
  • $$300^{\circ}$$
  • $$327^{\circ}$$
The relation between the internal energy $$U$$ and adiabatic constant $$\gamma$$ is
  • $$\displaystyle U=\frac{PV}{\gamma-1}$$
  • $$\displaystyle U=\frac{PV^{\gamma}}{\gamma-1}$$
  • $$\displaystyle U=\frac{PV}{\gamma}$$
  • $$\displaystyle U=\frac{\gamma}{PV}$$
Energy of all molecules of a monatomic gas having a volume V and pressure P is $$\frac{3}{2} PV$$. The total translational kinetic energy of all molecules of a diatomic gas at the same volume and pressure is
  • $$\dfrac{1}{2} PV$$
  • $$\dfrac{3}{2} PV$$
  • $$\dfrac{5}{2} PV$$
  • $$3 PV$$
A gas mixture consists of $$2\:mol$$ of oxygen and $$4\:mol$$ of argon at temperature $$T$$. Neglecting all vibrational modes, the total internal energy of the system is
  • $$4RT$$
  • $$15RT$$
  • $$9RT$$
  • $$11RT$$
A cylinder of capacity $$20\:L$$ is filled with $$H_2$$ gas. The total average kinetic energy of translatory motion of its molecules is $$1.5\times 10^5\:J$$. The pressure of hydrogen in the cylinder is
  • $$2\times 10^6\:N/m^2$$
  • $$3\times 10^6\:N/m^2$$
  • $$4\times 10^6\:N/m^2$$
  • $$5\times 10^6\:N/m^2$$
According to Kinetic theory of gases, molecules are:
  • perfectly inelastic particles in random motion
  • perfectly elastic particles in random motion
  • perfectly inelastic particles at rest
  • perfectly elastic particles at rest
A box contains $$N$$ molecules of a perfect gas at temperature $$T_1$$ and pressure $$P_1$$. The number of molecules in the box is doubled keeping the total kinetic energy of the gas same as before. If the new pressure is $$P_2$$ and temperature is $$T_2$$, then
  • $$P_2=P_1$$, $$T_2=T_1$$
  • $$P_2=P_1$$, $$\displaystyle T_2=\frac{T_1}{2}$$
  • $$P_2=2P_1$$, $$T_2=T_1$$
  • $$P_2=2P_1$$, $$\displaystyle T_2=\frac{T_1}{2}$$
Gaseous hydrogen contained initially under standard conditions in a sealed vessel of volume $$V= 5L$$ was cooled by $$\Delta T = 55 K$$. The internal energy of the gas will change by
  • $$-255 J$$
  • $$200 J$$
  • $$250 J$$
  • $$-200 J$$
Two containers of equal volume contain the same gas at pressures $$P_1$$ and $$P_2$$ and absolute temperatures $$T_1$$ and $$T_2$$, respectively. On joining the vessels, the gas reaches a common pressure $$P$$ and common temperature $$T$$. The ratio $$\displaystyle\frac{P}{T}$$ is equal to
  • $$\displaystyle\frac{P_1}{T_1}+\frac{P_2}{T_2}$$
  • $$\displaystyle\frac{P_1T_1+P_2T_2}{{(T_1+T_2)}^2}$$
  • $$\displaystyle\frac{P_1T_2+P_2T_1}{{(T_1+T_2)}^2}$$
  • $$\displaystyle\frac{P_1}{2T_1}+\frac{P_2}{2T_2}$$
The ratio of kinetic energy to potential energy for solids is
  • $$\displaystyle \frac{Ek}{U}<1$$
  • $$\displaystyle \frac{Ek}{U}>1$$
  • $$Ek=U$$
  • $$Ek>U$$
The correct curve for a stable diatomic molecule is
A vessel of volume 4 litres contains a mixture of 8 g of O$$_2$$, 14 g of N$$_2$$ and 22g of CO$$_2$$ at 27$$^o$$C. The pressure exerted by the mixture is
  • $$5 \times 10^6 N/m^2$$
  • $$6 \times 10^3 N/m^2$$
  • 10 atmosphere
  • $$7.79 \times 10^5 N/m^2$$
A vessel contains $$1$$ mole of O$$_2$$ (molar mass $$ 32 gm$$) at a temperature $$T$$. The pressure is $$P$$. An identical vessel containing $$1$$ mole of He (molar mass $$4 gm$$) at a temperature $$2T$$ has a pressure :
  • P
  • $$\displaystyle \frac{P}{8}$$
  • 2P
  • 8P
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