Respuesta :
Given,
The mass of the iron, m=100 kg
The initial temperature of the iron, T₁=25 °C=298.15 K
The melting point of the iron, T₂=1538 °C=1811.15 K
The specific heat of the iron, c=4.5×10² J/kg°C
The latent heat of fusion of iron, L_f=2.66×10⁵ J/kg
The heat needed to raise the temperature of the iron to 1811.15 K is given by,
[tex]\begin{gathered} Q_1=mc\Delta T \\ =mc(T_2-T_1) \end{gathered}[/tex]The heat required to change the phase of the iron from solid to liquid is
[tex]Q_2=mL_f[/tex]Thus the total heat required is,
[tex]\begin{gathered} Q=Q_1+Q_2_{} \\ =mc(T_2-T_1)+mL_f \end{gathered}[/tex]On substituting the known values,
[tex]\begin{gathered} Q=100\times4.5\times10^2\times(1811.15-298.15)+100\times2.66\times10^5 \\ =94.68\times10^6\text{ J} \end{gathered}[/tex]Thus the thermal energy that must be supplied is 94.68×10⁶ J
