Air at $25\backslash$deg C and a dew$-$point temperature of $0\backslash$deg C flows past the open end of a vertical tube filled with water at $25\backslash$deg C$.$ The tube has an inside diameter of $0\mathrm{.}83$ inch, and the liquid level is $0\mathrm{.}5$ inch below the top of the tube. The diffusivity of water in air at $25\backslash$deg C is $0\mathrm{.}256$ cm$^2.$

a$)$ calcule a velocidade de transferencia de massa da agua no ar sabendo que a pressao de vapor da agua a $25$ graus celsio $24$mmHg

b$)$ que tempo levara para o nivel do liquido no tubo cair $3$ in$?$