Practice question
Question
A 0.1kg iron block at 200∘C is dropped into 0.4kg water at 30∘C in a 0.05kg copper calorimeter at 30∘C. Find the final temperature. (Specific heat of iron = 450J kg−1K−1, water = 4186J kg−1K−1, copper = 386J kg−1K−1)
Explanation
0.1×450×(200−T) = (0.4×4186+0.05×386)×(T−30). 9000−45T = (1674.4+19.3)×(T−30) = 1693.7T−50811. 9000+50811 = 1693.7T+45T. 59811 = 1738.7T⇒T≈34.4∘C. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 34.4°C. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.
Discussion
Comments
Please log in to join the discussion.
Login to commentNo comments yet. Be the first to start the discussion.