Heat is removed from a molten metal of mass $$2$$ $$kg$$ at a constant rate of $$10$$ $$kW$$ till it is completely solidified. The cooling curve is shown in the figure.

Assuming uniform temperature throughout the volume of the metal during solidification, the latent heat of fusion of the metal (in $$kJ/kg$$) is ______________

A $$300$$ $$mm$$ thick slab is being cold rolled ussing roll of $$600$$ $$mm$$ diameter. If the coefficient of friction is $$0.08,$$ the maximum possible reduction (in $$mm$$) is _______

A $$300$$ $$mm$$ thick slab is being cold rolled using roll of $$600$$ $$mm$$ diameter. If the coefficient of friction is $$0.08,$$ the maximum possible reduction (in $$mm$$) is _______________

Under optimal conditions of the process the temperatures experienced by a copper work piece in fusion welding, brazing and soldering are such that