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

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