Mathematical and Physical Journal
for High Schools
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# Problem P. 4503. (January 2013)

P. 4503. The pressure and the volume of a sample of 0.4 moles Helium gas is doubled. Initially its pressure was 105 Pa, and its volume was 10 dm3. Determine those quantities from the list below which can be given uniquely:

a) The work done on the gas;

b) The heat given to the gas;

c) The change in the energy of the gas.

(4 pont)

Deadline expired on February 11, 2013.

Sorry, the solution is available only in Hungarian. Google translation

Megoldásvázlat. A gázon végzett munka és a gázzal közölt hő nagyságát nem határozza meg a gáz kezdeti és végállapota, ezek kiszámításához a közbenső állapotokat is kellene ismernünk. A gáz energiaváltozása:

$\displaystyle \Delta E=\frac{3}{2}p_1V_1-\frac{3}{2}p_0V_0=\frac{9}{2}p_0V_0=4{,}5~\rm kJ.$

### Statistics:

 132 students sent a solution. 4 points: 57 students. 3 points: 23 students. 2 points: 13 students. 1 point: 33 students. 0 point: 6 students.

Problems in Physics of KöMaL, January 2013