An ideal gas absorbs 100 J of heat and performs 25 J of work at constant pressure. Find its degrees of freedom.
Physics · Mixed Chapter
JEE Main Practice

Question

An ideal gas absorbs 100 J of heat and performs 25 J of work at constant pressure. Find its degrees of freedom.

G1 Physics · Accepted Answer

Step 1: ΔU=Q−W=100−25=75 J. Step 2: For isobaric ideal gas expansion, W=nRΔT=25 J. Step 3: ΔU=(f/2)nRΔT=(f/2)×25 J. Step 4: 75=25f/2 ⇒f=6.