Page 68 - SP015 Past Years PSPM Chapter 6 -14 Ver 2020

PHYSICS PSPM SEM 1 1999 - 2017

PSPM 2007/2008 SF017/2 No. 8(b)

13. By how many percent will the rms speed of an ideal gas molecules change if the gas
temperature increases by 50%? [3 m]

PSPM 2010/2011 SF017/2 No. 8(b)

14. The root mean square (rms) speed of gas molecules is to be reduced by 1%. If the gas
temperature is 27 C, at what temperature should it be cooled down? [3 m]

PSPM 2015/2016 SF016/2 No. 8(b)(ii)

-4
15. Calculate the rms speed of helium atoms at temperature 1  10 K. Molar mass of
-1
helium is 4 g mol . [2 m]

PSPM 2017/2018 SF016/2 No. 8(b)(i)

-3
3
16. A 5  10 m tank contains nitrogen at temperature 27 C and pressure 1.2 atm. The gas
pressure increases to 2.5 atm when the tank is heated. Given the molar mass of nitrogen
-1
is 28 g mol , calculate the change in the rms speed of the nitrogen molecules. [4 m]

Molecular Kinetic Energy and Internal Energy

PSPM 2007/2008 SF017/2 No. 8(a)

17. Write an equation for the average translational kinetic energy of molecules of an ideal
gas in terms of the absolute temperature of the gas. [1 m]

PSPM 2016/2017 SF016/2 No. 8(b)(i), (ii)

18. (a) Define the degree of freedom of gas molecules. [1 m]

(b) State the principle of equipartition of energy. [1 m]

PSPM 2006/2007 SF017/2 No. 14(b)

19. Distinguish heat and internal energy in the context of kinetic theory of gas. [3 m]

PSPM JUN 1999/2000 SF015/2 No. 7(b)

20. Explain the concept of internal energy of an ideal gas and state the types of degree of
freedom. [2 m]

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