Thermal energy is the energy generated from heat. This heat is produced by the movement of small particles within an object. The faster the particles move, the more the heat is generated. Thermal energy is responsible for the temperature of the system and a part of the total energy of the system which is the sum of potential energy and kinetic energy.
The thermal energy is usually expressed by Q. It is directly proportional to the mass of the substance, temperature difference, and the specific heat.
The SI unit of thermal energy is Joules(J).
Formula of Thermal Energy
The thermal energy formula is given by
Where
Q = thermal energy,
m = mass of the given substance,
c = specific heat, and
ΔT = temperature difference.
Solved Examples
Example 1
Determine the thermal energy of a substance whose mass is 6 kg and specific heat is 0.030 J/kg°c. The temperature difference of this system is given at 20°c.
Solution:
Given:
m = 6 kg,
c = 0.030J/kg°c,
ΔT = 20°c
The thermal energy formula is given by,
Q = mcΔT
   = 6 x 0.030 x 20
 Q = 3.6 J
Example 2
A 5 kg substance undergoes temperature difference of 60°C whose specific heat is 0.07 J/kg°C, determine the thermal energy.
Solution:
Given:
m = 5kg,
c = 0.07J/kg°C,
ΔT = 60°C
The for thermal energy formula is given by,
Q = mcΔT
   = 5×0.07×60
Q = 21 J
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