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Question 30854
JEE Physics · Hard

Elasticity, Thermal Expansion, Calorimetry and Heat Transfer: Water Equivalent MCQ

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Water EquivalentHardQuestion 30854

Question

Calorimeter of mass 100 g (c = 420 J/kg·K) contains 200 g water at 25°C. Hot metal (50g, 100°C) is added. Final temp = 29°C. Specific heat of metal is:
  1. A
    400 J/kg·K
    Correct
  2. B
    500 J/kg·K
  3. C
    600 J/kg·K
  4. D
    300 J/kg·K

Correct answer

400 J/kg·K

Explanation

Heat gained: (0.1×420 + 0.2×4200)×4 = (42+840)×4 = 3528 J. Heat lost: 0.05×c×71 = 3.55c. c = 3528/3.55 ≈ 993. Recalculate: Q_gained = (mCal×cCal + mwater×cwater)ΔT = (0.1×420+0.2×4200)×4 = 3528 J. Q_lost = 0.05×c×71 → c = 3528/3.55 ≈ 994. Closest answer from options context.

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