Question

Air at 33°C receives heat at constant volume until its temperature reaches 933°C. Determine the heat added per kilogram assuming C_v = 0.718 kj/kgK. 
1. 718.18 kJ/kg
2. 918.22 kJ/kg
3. 549.4 kJ/kg
4. 646.2 kJ/kg

Answer 1

Correct Answer - Option 4 : 646.2 kJ/kg

Concept:

Heat added at constant volume is given by

H = C_v (T₂ - T₁)

Where Cv = Specific heat

Calculation:

Given:

T₁ = 33°C, T₂ = 933°C, Cv = 0.718 kJ/kg K

Using, H = Cv (T2 - T1)

H = 0.718 (933 - 33)

H = 646.2 kJ/kg