Acopper sheet of thickness 2 mm has an initial temperature of 140°c. it is suddenly quenched in liquid water, resulting in boiling at its two surfaces. for boiling, newton’s law of cooling is expressed as , where is the solid surface temperature and is the saturation temperature of the fluid (in this case 100°c). the convection heat transfer coefficient may be expressed as . determine the time needed for the sheet to reach a temperature of 104°c.