If a leaf is to maintain a temperature of 40.0\deg C (reasonable for a leaf), it must lose 255 W/m2 by transpiration (evaporative heat loss). Note that the leaf also loses heat by radiation, but we will ignore this. How much water is lost after 1.00 h through transpiration only? The area of the leaf is 0.00200 m2. Heat of vaporization for water is 2256 kJ/kg (see Table B.5).