Water at 15^ ^ ^ C is contained inside a closed, thermally insulated copper vessel. The temperature increases to 17^ ^ ^ C after the vessel is vigorously shaken for 15 minutes. The mass of the water is 200 g and the

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Correct answer: B. 1764 J

The increase in the internal energy of the system is given by the total heat capacity of the system multiplied by the change in temperature.

The change in temperature is

\Delta T = 17^{}^{{}^{\circ}} \text{C} - 15^{}^{{}^{\circ}} \text{C} = 2 \text{ K}

.

The total heat capacity of the system is the sum of the heat capacities of the water and the copper vessel:

C = m_w c_w + m_c c_c

Substituting the given values:

C = (0.2 \text{ kg}) \times (4200 \text{ J kg}^{-1} \text{ K}^{-1}) + (0.1 \text{ kg}) \times (420 \text{ J kg}^{-1} \text{ K}^{-1})

C = 840 \text{ J K}^{-1} + 42 \text{ J K}^{-1} = 882 \text{ J K}^{-1}

The increase in internal energy is:

\Delta U = C \Delta T

\Delta U = 882 \times 2 = 1764 \text{ J}

Water at 15^ ^ ^ C is contained inside a closed, thermally...

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