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

Question

An ideal gas absorbs 100 J of heat while doing 25 J of work at constant pressure. Find its molecular degrees of freedom f.

G1 Physics · Accepted Answer

Step 1: First law ΔU=Q−W=100−25=75 J. Step 2: For ideal gas with f active degrees of freedom, ΔU=(f/2)nRΔT. Step 3: In isobaric process W=PΔV=nRΔT=25 J. Step 4: 75=(f/2)×25 ⇒f=6.