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ChemistryJEE Main 23 Jan 2026, Shift 1·Q8·MCQ·Easy–moderate

Thermodynamics · First law sign conventions

A cup of water at 5∘^\circC (system) is placed in a microwave oven and the oven is turned on for one minute during which, the water begins to boil. Which of the following option is true ?
  1. (1)q=+q = +ve, w=0w = 0, ΔU=−\Delta U = -ve
  2. (2)q=+q = +ve, w=−w = -ve, ΔU=+\Delta U = +ve
  3. (3)q=−q = -ve, w=−w = -ve, ΔU=−\Delta U = -ve
  4. (4)q=+q = +ve, w=−w = -ve, ΔU=−\Delta U = -ve

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See the full 23 Jan 2026, Shift 1 paper