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Question
Decide the unit for specific heat capacity.
Solution
- The amount of heat (Q) required to change the temperature of a substance is directly proportional to:
a. the mass of the substance (m).
b. change in temperature of the substance (ΔT).
∴ Q ∝ m and Q ∝ ΔT
∴ Q ∝ mΔT
∴ Q = cmΔT ....(1)
where ‘c’ is specific heat or specific heat capacity of a substance. From equation (1),
c = `"Q"/("m" Delta "T")` ....(2) - SI unit:
As SI unit of heat is J, mass is kg and change in temperature is °C, SI unit of specific heat capacity is J/kg °C - C.G.S. unit:
As CGS unit of heat is calorie, mass is g and change in temperature is °C, CGS unit of specific heat capacity is cal/g °C
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