A calorically perfect gas (specific heat at constant pressure $1000 \: J/kg .K$) enters and leaves a gas turbine with the same velocity. The temperatures of the gas at turbine entry and exit are $1100 \: K $and $400 \: K$, respectively. The power produced is $4.6\: MW$ and heat escapes at the rate of $300 \: kJ/s$ through the turbine casing. The mass flow rate of the gas (in $kg/s$) through the turbine is
- $6.14$
- $7.00$
- $7.50$
- $8.00$