Page 77 - SP015 Past Years PSPM Chapter 6 -14 Ver 2020

PSPM SP015

PSPM 2016/2017 SF016/2 No. 8(c)

28. p (kPa)

1000 A

500 B

0 0.02 0.04 V (m )
3

FIGURE 14.6

FIGURE 14.6 shows a p-V graph of an isothermal process at 600 K for 2 moles of ideal
4
gas in a cylinder with frictionless piston. If the internal energy at point A is 2.5  10 J,
does the heat being absorbed or released during the process from A to B? Justify your
answer. [5 m]

PSPM 2017/2018 SF016/2 No. 8(c)

29.
p (N m )
-2

4 B C
7  10

2  10
4
A
3
V (m )
-3
-3
3  10 6  10

FIGURE 14.7

FIGURE 14.7 shows a series of thermodynamic processes ABC. During the process
AB and process BC, 120 J of heat and 500 J of heat are added respectively. Calculate
the change in the internal energy in the process ABC. [5 m]

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