Multiple choice

Initially a beaker has $100$g of water at temperature $90^oC$. Later another $600g$ of water at temperature $20^oC$ was poured into the beaker. The temperature, T of the water after mixing is?

  1. $20^oC$
  2. $30^oC$
  3. $45^oC$
  4. $55^oC$
  5. $90^oC$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Using the principle of calorimetry: m1*c*(T-T1) + m2*c*(T-T2) = 0. 100*(T-90) + 600*(T-20) = 0. 100T - 9000 + 600T - 12000 = 0. 700T = 21000. T = 30.

AI explanation

Using the method of mixtures and the principle of heat exchange, we equate the heat lost by the warm water to the heat gained by the cool water using $100 * (90 - T) = 600 * (T - 20)$. This simplifies to $9000 - 100T = 600T - 12000$, which further reduces to $21000 = 700T$. Solving for T gives a final temperature of $30$ degrees Celsius.

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