Answer:
71195 seconds or 19.8 hours
Explanation:
Because the steel will be melted, beginning from room temperature, energy is needed to heat it from room temperature to 1600°C and another to melt it at 1600°C.
We take room temperature to be 27°C, the specific heat capacity of steel to be 420 J/kg/K and the specific latent heat of fusion of steel to be 440 J/kg.
The heat required to heat the steel from room temperature to 1600°C is given by
is the mass,
is the specific heat capacity and
is the change in temperature.
The heat required to melt it at 1600°C is
is the mass and
is the specific latent heat of fusion of steel.
Adding both, the heat required is
Because the oven is 65% efficient, its output power =
Now, energy = power * time
Time = Energy/power