The mass transfer coefficient from a free water surface to an adjacent moving air stream has been found to be $0\mathrm{.}017$ kg$/$m$\text{'}$s$.$ The water surface area and temperature are $1$ m$^2$ and $27\backslash$deg C$.$ If the air stream has a dry$-$bulb temperature of $45\backslash$deg C and the rate evaporation from the water surface is $6\mathrm{.}8\backslash$times $10-5$ kg$/$s$,$ calculate:$($i$)$ the humidity and relative humidity of the air stream.$($i$)$ rate of supply of heat energy needed for the evaporation.