First law of thermodynamicsऊष्मागतिकी का प्रथम नियम

NCERT Fig 11.4 · interactive diagram

Parts and their functions

• Heat supplied ΔQ (दी गई ऊष्मा ΔQ) — Energy that flows in because of a temperature difference (positive when supplied to the system).
• Internal energy U (आंतरिक ऊर्जा U) — Sum of the kinetic and potential energies of the molecules; a state variable. Part of ΔQ raises it.
• Work done by the gas ΔW (गैस द्वारा किया कार्य ΔW) — ΔW = P ΔV when the piston moves out (positive when done by the system).
• Movable piston (गतिशील पिस्टन) — Lets the gas change volume and do work on the surroundings.
• Cylinder (सिलिंडर) — Holds a fixed amount of gas — the system.
• ΔQ = ΔU + ΔW (ΔQ = ΔU + ΔW) — Energy conservation: heat supplied = rise in internal energy + work done by the system.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 11.4. Report a mistake