Which object has the most thermal energy?

A. 40 kg of water at 20°C
B. 5 kg of water at 10°C
C. 40 kg of water at 10°C
D. 5 kg of water at 20°C



Answer :

To determine which object has the most thermal energy, we consider each object's mass and temperature.

Thermal energy, [tex]\( Q \)[/tex], is calculated using the formula:
[tex]\[ Q = \text{mass} \times \text{specific heat capacity} \times \text{temperature} \][/tex]
Since we are dealing with the same substance (water) for all objects, and the specific heat capacity of water is a constant value, we can compare the products of mass and temperature directly for each object.

Let's examine each object:

1. Object A: 40 kg of water at 20°C
[tex]\[ Q_A = 40 \times 20 = 800 \][/tex]

2. Object B: 5 kg of water at 10°C
[tex]\[ Q_B = 5 \times 10 = 50 \][/tex]

3. Object C: 40 kg of water at 10°C
[tex]\[ Q_C = 40 \times 10 = 400 \][/tex]

4. Object D: 5 kg of water at 20°C
[tex]\[ Q_D = 5 \times 20 = 100 \][/tex]

Now we compare these values:
- [tex]\( Q_A = 800 \)[/tex]
- [tex]\( Q_B = 50 \)[/tex]
- [tex]\( Q_C = 400 \)[/tex]
- [tex]\( Q_D = 100 \)[/tex]

Among these, the maximum thermal energy is [tex]\( 800 \)[/tex].

Thus, Object A (40 kg of water at 20°C) has the most thermal energy.