Two thermally insulated vessels 1 and 2 are filled with air at temperatures ( T1,T2 ), volumes ( V1,V2 ) and pressures ( p1,p2 ) respectively. If the valve joining the two vessels is opened, the temperature inside the vessel at equilibrium will be ( P = common pressure)
(1) T1+T2
(2) (T1+T2)/2
(3) p1V1T2+p2V2T1T1T2p(V1+V2)
(4) p1V1T2+p2V2T1T1T2(p1V1+p2V2)