Question

A vessel contains 110 g of water. The heat capacity of the vessel is equal to 10 g of water. The initial temperature of water in vessel is 10°C. If 220 g of hot water at 70°C is poured in the vessel, the final temperature neglecting radiation loss, will be

• A. 70°C
• B. 80°C
• C. 60°C
• D. 50°C

Answer 1

Answer: (D)

50°C

Answer 2

Let final temperature of water be θ

Heat taken = Heat given

110 ×1 (θ – 10) + 10 (θ – 10) = 220 × 1 (70 – θ)

⇒ θ = 48.8°C ≈ 50°C.