Given,
Mass of the iron, m=4.8 kg
Initial temperature, T₁=22 °C=295.15 K
Final temperature, T₂=400 °C=673.15 K
The specific heat capacity of the iron is, c=462 J/kg·K
The heat energy required is calculated using the formula,
[tex]Q=mc\Delta T=mc(T_2-T_1)[/tex]On substituting the known values,
[tex]Q=4.8\times462(673.15-295.15)=838.25\text{ kJ}[/tex]Therefore the energy required is 838.25 kJ