The average degrees of freedom per molecule of a gas are 6. The gas performs 25 J of work in a process when it is expanded at constant pressure. Amount of heat absorbed by the gas is 25 × x. Value of x is:
Physics · Mixed Chapter
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Question

The average degrees of freedom per molecule of a gas are 6. The gas performs 25 J of work in a process when it is expanded at constant pressure. Amount of heat absorbed by the gas is 25 × x. Value of x is:

Physics · Mixed Chapter

G1 Physics · Accepted Answer

Step 1: At constant pressure the work done is W=nRΔT=25 J. Step 2: With f=6 molecular degrees of freedom, C_V=fR/2=3R and C_P=C_V+R=4R. Step 3: Heat supplied Q=nC_PΔT=(C_P/R)W=4×25=100 J. Step 4: Q=25x gives x=4.