A fixed mass of an ideal gas slowly releases 1500 j of heat and as a result contract slowly,at a constant pressure 2.0 x 104 pa, from a volume of 0.025 M3. What is the effect on the internal energy of the gas?
A it decrease by 2000 j.
B it decreases by 1000 j.
C it is unchanged.
D it increase by 1000 j