Conceptual question for Thermodynamics

PART 4

1. The amount of energy radiated by a body depends on
a.The nature of the surface
b. The area of the surface
c. Temperature of the surface
d. all the above

2. The wavelenght of the radiation emitted by the body depends on
a.The nature of the surface
b. The area of the surface
c. Temperature of the surface
d. all the above

3.A solid sphere and a hollow sphere of same material and size are heated to the same temperature and allowed to cool in the same surounding.If the temperature diffrence between the sphere and surrounding is T.then
a. Both sphere will cool at the same rate for all values of T
b Hollow sphere will cool faster for all values of T
c. Solid sphere will cool faster for all values of T
d. Both sphere will cool at the same rate for small values of T

4. An ideal black body is thrown in the furnace.It is observed that
a. Intially it is the darkest body and at later times the brightest
b. it is the darkest body all the times
c. It cannot be distinguish at all the times
d. Intially it is the darkest body and at later times It cannot be distinguish


5.In which of the following process,convection does not takes place
a. sea and land breeze
b.boiling of the water
c.heating air around the furnace
d.warming of glass of bulb due to filament

6.One end of a metal rod is kept in a furnace.In steady state,the temperature of the rod
a. Increase
b decrease
c. remains constant
d is non uniform

7 what is true for black body
a e=a=1
b emit radiation and absorb radiation
c. refract radiation
d none of the above

8.which one is true about thermal radiation
a. all bodies emit radiation at all temperature
b. Good reflectors are good emitters of thermal radiation
c. Thermal radiation travel in free space with the velocit of light
d. Thermal radiation are not reflected from the mirror



Solutions

PLease take a look at other parts also
Conceptual Questions Part 1
Conceptual Questions Part 2
Conceptual Questions Part 3

Conceptual question for Thermodynamics

PART 3

1.In a given process of an ideal gas,dW=0 and dQ<0 ,then for a gas
a.dT <0
b. dV>0
c.dP=0
d. dT>0

2.what is true for a free expansion process
a. dW=0
b. dQ=0
c. dU=0
d. all the above

3. Consider the following two statement
A.If heat is added to the system,it temperature must increase
B.If dW >0 then dV >0
a A & B both are correct
b A is correct only
c. B is correct only
d A &B both are wrong

4.what is true of Isothermal process
a. dT>0
b. dT=0
c. dQ=dW
d. none of the above

5. if dU=-dW for a process,the process is
a. Adiabatic
b. Isothermal
c. Isobaric
d. None of the abobe

6.What is true of a cyclic process
a.ΔQ=ΔW
b ΔU=0
c.ΔU >0
d None of the above

7. An ideal gas is taken from state A(P,V) to state B(P/2,2V) along a straight line path in P-V diagram.Select the correct statement from the following
a.The workdone by the gas in process A to B exceeds the work that would be done by it if the system were taken from A to B along a isotherm
b.in the T-V diagram ,the path AB becomes a part of a parabola,
c. In the P-T diagram,the path becomes a part of a parabola
d.In going from A to B,the temperature T of the gas first increase to a maximum and then decrease

8.Let W1,W2 are the workdone in the two process A & B by an ideal gas.ΔTA=ΔTB. Let CA and CB are the molar heat capacities in two process
Also W1 > W2. whic of the following is correct
a.CA=CB
b.CA < CB
c. CA > CB
d None of the above.

9.which of the following is correct
a. Molar heat capacity is 0 for PVy=Constant
b. Molar heat capacity is infinity in adiabatic process
c. Internal energy does not change in Isothermal Process
d. All the above

10.An ideal gas is taken from state A(P1,V1) to state B(P2,V2) by two method X & Y..which of the following is correct
a.ΔQ1-ΔW1=ΔQ2-ΔW2
b.ΔU1=ΔU2
c. ΔQ1+ΔW1=ΔQ2+ΔW2
d. None of the above

Solutions

Please take a look at other parts also
Conceptual Questions Part 1
Conceptual Questions Part 2
Conceptual Questions Part 4

Conceptual Question of Thermodynamics

PART 2


1.which one is not the assumption in kinetic theory of gases
a.the molecules of the gas are in continual random motion
b. The molecules interact during the collison
c. The molecules are tiny hard sphere undergoing inelastic collision
d. The collison are of short duration

2. There are two statement
A. Equal volumes of all gases at the same temperature T and pressure P contain an equal no of Molecules
B.the no of molecules in one mole of any gas is 6.0255 * 1022.
which one of the following is correct
a. A and B both
b. A only
c B only
d. A and B both are incorrect

3.There are two statement about Ideal gases
A. The Vrms of gas molecules depends on the mass of the gas molecule and the temperature
B. The Vrms is same for all the gases at the same temperature
which one of the following is correct
a. A and B both
b. A only
c B only
d. A and B both are incorrect

4.Choose the correct statement of the following
a. The pressure of the gas is equal to the total kinetic energy of the molecules in a unit volume of the gas
b. The product of pressure and volume of the gas is always constant
c. The average kinetic energy of molecule of the gas is proportional to its absolute temperature
d. The average kinetic energy of molecule of the gas is proportional to the square root of its absolute temperature

5..which one is true according Vander Waal gas equation
a. The attractive forces between the molecules is not negligible
b Volume of the molecules is negligible as compared to the volume occupied by the gas
c. Volume of the molecules is not negligible as compared to the volume occupied by the gas
d. The attractive forces between the molecules is negligible


Solutions

PLease take a look at other parts
Conceptual Questions Part 1
Conceptual Questions Part 3
Conceptual Questions Part 4

Conceptual questions of Thermodynamics

PART 1

1. A rod of length L having coefficent of Linear expansion α is lying freely on the floor.it is heated so that temperature changes by ΔT .Find the longitidunal strain developed in the rod
a. 0
b. αΔT
c. -αΔT
d. none of the above

2.if a is coefficent of Linear expansion,b coefficent of areal expansion,c coefficent of Volume expansion.Which of the following is true
a. b=2a
b. c=3a
c. b=3a
d. a=2b

3.which is of them is not used as the measurable properties in thermometer?
a.Resistance of platinum ire
b.Constant volume of gas
c.Contant pressure of gas
d.None of the above

4.when a solid metalic sphere is heated.the largest percentage increase occurs in its
a.Diameter
b. Surface area
c. Volume
d. density

5.the density of the liquid depends upon
a. Nature of the liquid
b. Temperature of the liquid
c. Volume of the liquid
d. Mass of the liquid

6. A metallic sphere has a cavity of diameter D at its center.If the sphere is heated,the diameter of the . cavity will
a. Decrease
b. Increase
c. Remain unchanged
d. none of the above

7.A metallic circular disc having a circular hole at its center rotates about it axis passing through the center and perpendicular to it plane.when the disc is heated
a. Its speed will decrease
b. Diameter will increase
c. Moment of inertia will increase
d. its speed will increase

Solutions

Please take a look at Parts also
Conceptual Questions Part 2
Conceptual Questions Part 3
Conceptual Questions Part 4

Objective question of Thermodynamics for IITJEE/AIEEE

1. An ideal gas is taken through the cycle abcda.calculate the work done by the gas

a,3pv
b,2pv
c,pv
d,none of the above

2.An ideal gas was taken from state a to state b in three ways...If W1,W2,W3 are workdone by the gas in patch abc,adc and ac respectively.Which one of the following is true

a. W1 > W2 > W3
b. W1 > W3 > W2
c. W3 > W2 > W1
d. None of the above

3. An ideal gas is taken through the cycle aba.calculate the work done by the gas

a 2pv-1/2πv2
b 2pv+1/2πv2
c 2pv
d None of the above

4. N rods of equal length L and equal crossestion area having thermal conductivities from k to nk respectivity are joined together to form rod of length NL.What is the ratio of Thermal conductivity of whole rod to the thermal conductivity of Nth Rod.
a.1/2(n+1)
b.n+1
c.n
d.1

5.The speed of the four molecules are v,2v,3v,4v.What is the rms speed of the gas
a.v√7
b. 7v
c.v√2
d.v√7.5


6.A sample of gas expands from volume V1 to V2.The amount of workdone by the gas is greatest when the expansion is
a. Isothermal
b.Adiabatic
c. Isobaric
d. Equal in all the cases

7.A sample of an ideal gas has volume 2V,Pressure 2P and Temperature T.The mass of the each molecules of the gas is m.The density of the gas is
a. mkT
b. 2P/kt
c. P/kVT
d. 2Pm/kT

8. EN and EH respectivity are the average kinetic energy of the molecules of Nitrogen and Hydrogen.if the two gas are at the same temperature which of the following statement is true?
a. EN > EH
b. EN = EH
c. EN < EH
d. Nothing can be said

9. One mole of a diatomic gas is taken through the process PTn=C where n and C are constant.if the heat capacity of the gas is negative,then the value of n may be
a. 4
b. 3
c. -4
d. -3

10.Certail Ideal gas is found to be obey PV3/2=C during an adiabatic process.If such a gas at intial temperature T is adaiabatically compressed to half the intial volume.Its final temperature will be
a. T√2
b. 2T
c. 2T√2
d. 4T

Solutions

Some points to note

1. Isothermal Process
Pv=constant
VdP+PdV=0
-VdP/dV=P
Now Bulk Modulus= -VdP/dV
So Bi=P

Adiabatic Process
PVy=constant
VydP+PyVy-1dV=0
So Ba=yP

2. if A sold sphere and a hollow sphere having same material and size are heated to same temperature and allowed to cool in the same surrounding ,it has been found that hollow sphere cools faster than solid sphere

Objective Thermodynamics question for IITJEE

1. In a given process on an ideal gas,dW>0 and dQ=0 .Then for the gas
a) Temperature will decrease
b) Temperature will increase
c) volume will decrease
d) none of above

2.A cylinder of diameter D and of thermal conductivity k is surrounded by a cylinderical shell of inner diameter D and Outer Diameter 2D made of material of thermal conductivity 2k.The effective thermal conductivity of the system is
a) 5k/3
b) 4k
c) 5k/4
d) 7k/4

3.what all is true for a adiabatic process
a) dQ=0
b) dW=-nCvdT
c) TVy-1=constant
d) all the above three

4. what is the ratio of r.m.s speed of H2 to O2
a) 4:1
b) 1:4
c) 2:1
d) 1:2

5.The coefficent of linear expansion of an inhomogenous rod changes linearly from α1 to α2 from one end to the other end of the rod.The effective coefficient of linear expansion of the rod is

a α12
b 1/2(α12)
c. √α1α2
d. (α12)

Solutions

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