Practice question
Question
A 0.15kg copper block at 200∘C is dropped into 0.9kg water at 15∘C in a calorimeter of mass 0.1kg (specific heat = 386J kg−1K−1). Find the final temperature. (Specific heat of copper = 386J kg−1K−1, water = 4186J kg−1K−1)
Explanation
Heat lost = Heat gained. 0.15×386×(200−T) = (0.9×4186+0.1×386)×(T−15). 11580−57.9T = (3767.4+38.6)×(T−15) = 3806T−57090. 11580+57090 = 3806T+57.9T. 68670 = 3863.9T⇒T≈17.77∘C≈17.8∘C. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 17.8°C. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.
Discussion
Comments
Please log in to join the discussion.
Login to commentNo comments yet. Be the first to start the discussion.