Page 133 - text book form physics kssm 2020

Chapter 4
Heat
Specifi c Heat Capacity of Substance
Figure 4.9 shows a material engineer tries to choose a suitable metal
as building material. He needs a material that does not heat up Specifi c Heat Capacity
easily. Since the heat capacity of a material diff ers with its mass, he
needs to make his choice based on specifi c heat capacity instead
– which means he has to choose the material based on the heat
capacity of every 1 kg of each material.
http://bt.sasbadi.com/p4127

Which metal gets
hot slowly?

Figure 4.9 A material engineer is comparing specifi c heat capacity between diff erent metals

Specifi c heat capacity, c of a substance is the quantity of heat needed to raise
the temperature of 1 kg mass of the substance by 1°C.

Q
c = , where Q = quantity of heat supplied (J)
mΔθ
m = mass (kg)
Δθ = change of temperature (°C or K)

–1
–1
–1
Unit for c = J kg °C or J kg K –1
Quantity of heat, Q that is absorbed or released by an object can be
determined using the formula Q = mcΔθ.

SMART
For example, the specifi c heat capacity of the metal SMART INFO
aluminium is 900 J kg °C . Th is means 1 kg of aluminium
–1
–1
requires 900 J of heat to raise its temperature by 1°C. Q
Heat capacity, C = Δθ
Q
Specifi c heat capacity, c = mΔθ

127
127
4.2.2
4.2.2 127