One kg of a substance (initially solid of `0^(@)C`) is supplied heat at a concentration of

One kg of a substance (initially solid of `0^(@)C`) is supplied heat at a concentration of 2 kcal/min. suffificent of thermal expansion of the solid `(a)=4xx10^(-6)//.^(@)C` its temperature varies with increase shown. img src=" width="80%" Percentage change in volume of the solid in the first 150 sec is

concentration