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MHT CET202519 Apr 2025Morning ShiftChemistryThermodynamics (C)Actual

Calculate the change in internal energy of the system if 20 kJ of work is done on the system and it releases 10 kJ of heat in a particular reaction.

Options

  1. A30 kJ
  2. B10 kJ
  3. C-15 ~kJ
  4. D-20 ~kJ

Correct answer

B. 10 kJ

Step-by-step solution

The First Law of Thermodynamics gives the change in internal energy as U = q + w , where q is heat added to the system and w is work done on the system. Heat released by the system corresponds to q = -10 kJ , while work done on the system gives w = +20 kJ . Substituting these values yields U = (-10 kJ ) + (20 kJ ) = 10 kJ . The internal energy increases by 10 kJ , making B the correct answer.

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