- #1
Omar Nagib
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We have an ideal gas enclosed in cylinder whose top is covered by a piston of certain weight ##mg##. At this stage, the piston is at rest which means the force by which the gas acts on the piston (##F=PA## where ## P## is the gas pressure and ##A## is the cross sectional area of the cylinder) is equal to ##mg##.
Now if this system was subject to an isobaric process, then its temperature and volume changes with its pressure held constant(suppose ##T## and ##V## increase). But this is confusing, since during the process the piston is continuously changing its position, which implies its being acted upon by a certain net force; Now the weight of the piston ##mg## is constant, so the force ##F=PA## by which the gas acts on the piston must have increased, but since ##A## is constant, therefore ## P## must have increased; therefore ##P## is not constant.
So How isobaric process is physically possible?
Now if this system was subject to an isobaric process, then its temperature and volume changes with its pressure held constant(suppose ##T## and ##V## increase). But this is confusing, since during the process the piston is continuously changing its position, which implies its being acted upon by a certain net force; Now the weight of the piston ##mg## is constant, so the force ##F=PA## by which the gas acts on the piston must have increased, but since ##A## is constant, therefore ## P## must have increased; therefore ##P## is not constant.
So How isobaric process is physically possible?