Question

when a gas filled in a cylinder filled with movable piston is allowed to expand ,work done by gas is positive explain​

Answer 1

IN CHEMISTRY IT IS POSITIVE AS EVERYTHING IS OBSERVED WITH RESPECT TO SURROUNDING HENCE WHEN THE GAS EXPANDS WORK IS DONE BY THE SYSTEM ON THE SURROUNDING

BUT IN PHYSICS IT IS NEGATIVE AS IN PHYSICS EVERYTHING THING IS IN RESPECT TO THE SYSTEM HENCE WHEN THE GAS EXPANDS WORK IS DONE BY THE SYSTEM ON THE SURROUNDING WHICH IN TURN LEADS TO THE DECREASE IN INTERNAL ENERGY OF THE SYSTEM HENCE WORK DONE IS NEGATIVE

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