A mercury thermometer reads `99.25^(@)C` when immersed in a steam bath in such a way that the entire of its stem above is `0^(@)C` graduation is outside the bath. The temperature of the room is `20^(@)C`. When the whole of its steam is pushed into the bath, the thermometer reads `100.5^(@)C`. Calculate the coefficient of cubical expansivity of mercury. (Given theat linear expansivity of glass `=8xx10^(-6)K^(-1)`)
