Final answer:
A power station using coal with a heating value of 30 MJ/kg and producing 0.72 GW of electricity with an efficiency of 36% will use 2880 kg of coal in one hour.
Step-by-step explanation:
To calculate the amount of coal used in one hour by a power station, we need to consider the power output and efficiency of the station. In this case, the power station produces 0.72 GW (gigawatts) of electricity with an efficiency of 36%. We can calculate the amount of coal used by dividing the power output by the product of the efficiency and the heat of combustion of coal.
First, we convert the power output to joules by multiplying it by 10^9 (1 GW = 10^9 W). The number of joules can be calculated by multiplying the power output by the number of seconds in one hour (3600 seconds).
Then, we calculate the amount of coal by dividing the energy produced by the product of the efficiency and the heat of combustion of coal. The heat of combustion of coal is given as 30 MJ/kg (megajoules per kilogram).
Let's calculate the amount of coal used in one hour:
Power Output = 0.72 GW = 0.72 x 10^9 W = 0.72 x 10^9 J/s
Energy Produced in One Hour = Power Output x Time = 0.72 x 10^9 J/s x 3600 s = 2.592 x 10^12 J
Amount of Coal = Energy Produced / (Efficiency x Heat of Combustion) = 2.592 x 10^12 J / (0.36 x 30 x 10^6 J/kg) = 2.88 x 10^3 kg = 2880 kg
Therefore, the power station uses 2880 kg of coal in one hour.