question_answer 13)

A copper block of mass 2.5 kg is heated in a furnace to a temperature of \[{{500}^{o}}C\]and then placed on a large ice block. What is the maximum amount of ice that can melt. Specific heat of copper is \[m=8\cdot 0kg=8\times {{10}^{3}}kg\]\[\vartriangle T=?,\]Heat of fusion of water \[\vartriangle T=?,\]

Answer:

Here, mass of copper block, \[t=2\cdot 5\min =2\cdot 5\times 60=150s\]m Fall in temperature, \[c=0\cdot 91J{{g}^{-1}}\] Specific' heat of copper, \[^{\text{o}}{{\text{C}}^{\text{-1}}}\] Latent heat of fusion, \[\text{p }\!\!\times\!\!\text{ t=1}{{\text{0}}^{\text{4}}}\text{ }\!\!\times\!\!\text{ 150=15 }\!\!\times\!\!\text{ 1}{{\text{0}}^{\text{5}}}\text{J}\] Let the mass of ice melted be m' As, Heat-gained by ice = Heat lost by copper \[\therefore \] \[\vartriangle \text{Q=}\frac{\text{1}}{\text{2}}\text{ }\!\!\times\!\!\text{ 15 }\!\!\times\!\!\text{ 1}{{\text{0}}^{\text{5}}}\text{=7 }\!\!\times\!\!\text{ 5 }\!\!\times\!\!\text{ 1}{{\text{0}}^{\text{5}}}\text{J}\] \[\vartriangle \text{Q}\]