The vaccine solution held in capillary tubes contains a dilute amount of active

ingredient. The vaccine solution is stored in a $10$ cm long capillary tube with a

diameter of $0\mathrm{.}01$ cm $,$ but when the mouth of the tube is broken, the water in the

solution evaporates and diffuses to the surface. How long does it take for $1$ gram

of water to evaporate from the capillary tube? The tube is kept at $20C$ and the

vapor pressure of water at this temperature is $17\mathrm{.}5$ mmHg $.$ Again, at this

temperature, the diffusivity of water vapor is $0\mathrm{.}20$ cm $2.$

Take it as $/$s$.$ Take the pressure of the dry air at the mouth of the tube as

atmospheric pressure.