Question

question 3 of 20
which object has the most thermal energy?
a. 5 kg of water at 10°c
b. 40 kg of water at 10°c
c. 40 kg of water at 20°c
d. 5 kg of water at 20°c

Explanation:

Step1: Recall thermal - energy formula

Thermal energy $Q = mc\Delta T$. For water, specific - heat capacity $c$ is constant. When comparing samples of water, thermal energy depends on mass $m$ and temperature $T$. Higher mass and higher temperature mean more thermal energy.

Step2: Compare options

Option A has a mass of $m = 5$ kg and temperature $T = 10^{\circ}C$. Option B has $m = 40$ kg and $T = 10^{\circ}C$. Option C has $m = 40$ kg and $T = 20^{\circ}C$. Option D has $m = 5$ kg and $T = 20^{\circ}C$. Option C has the highest mass among non - discarded options and the highest temperature.

Answer:

C. 40 kg of water at 20°C