Due to cold weather a \( 1 \, \text{m} \) water pipe of cross-sectional area \( 1 \, \text{cm}^2 \) is filled with ice at \( -10^\circ \text{C} \). Resistive heating is used to melt the ice. Current of \( 0.5 \, \text{A} \) is passed through \( 4 \, \text{k}\Omega \) resistance. Assuming that all the heat produced is used for melting, what is the minimum time required?
(Given latent heat of fusion for water/ice \( 3.33 \times 10^{5} \, \text{J} \, \text{kg}^{-1} \), specific heat of ice \( = 2 \times 10^{3} \, \text{J} \, \text{kg}^{-1} \) and density of ice \( = 10^{3} \, \text{kg} / \text{m}^{3} \))