Specific heat of air at constant pressure is equal to

Question

Question

This question was previously asked in

BPSC AE Paper 5 (Mechanical) 2012 Official Paper

Answer 1

Explanation:

Specific heat:

specific heat is a quantity of energy required for a unit mass to change the temperature by 1 K or 1°C.
Specific heat is a function of operating temperature so it increases with an increase in operating temperature but incremental in value is negligible therefore we need to treat it is independent of temperature.
In the case of compressible medium-specific heat is defined on basis of constant pressure, constant volume. But in the case of the incompressible medium, both the specific heats are equal.
Specific heat is a property of medium which indicates the store or absorb of thermal energy. The more the specific heat more the ability to store energy more.

Important Points

Examples:
- C_water= 4.187 kJ/kg-K.
- C_iron= 0.45 kJ/kg-K
- (C_p)_air= 1.005 kJ/kg-K = 0.24 kcal.Kg^-1.C^-1
- (C_V)_air= 0.718 kJ/kg-K.

NOTE: 1 Calorie = 4.186 Joules