RDA stands for Recommended Daily Allowance. To determine the amount needed of a certain adult per day, we simply multiply the mass of the adult to the value of RDA. For this case, we do as follows:
Daily requirement = 12 mg/kg ( 78 kg ) = 936 mg of lysine = 936000 g
Celina should perform the following method to get pure water:
Boil the water in a pan, as the water boils it changes into gas (water vapours) these vapours should be cooled down through the process of condensation which changes gas into liquid form, Through this process germs would be killed due to high temperature and the salt will remain in the pan as salt has higher boiling point than water,
The energy of a photon is given by

where

is the Planck constant
f is the frequency of the photon
In our problem, the frequency of the light is

therefore we can use the previous equation to calculate the energy of each photon of the green light emitted by the lamp: