In a tub, $100 \mathrm{~kg}$ of water at $30^{\circ} \mathrm{C}$ absorbs $100 \mathrm{~J}$ from an electric heater. We can reasonably consider the water to be a reservoir in this process.

Question

Quizplus · Accepted Answer

The amount of heat absorbed by the water (100 J) is relatively small compared to the large mass of water (100 kg), and thus the temperature change of the water would be negligible, allowing it to act as a thermal reservoir.

In a Tub 100 kg100 \mathrm{~kg}100 kg Of Water At 30∘C30^{\circ} \mathrm{C}30∘C Absorbs 100 J100 \mathrm{~J}100 J

In a Tub $100 \mathrm{~kg}$ Of Water At $30^{\circ} \mathrm{C}$ Absorbs $100 \mathrm{~J}$