how is light energy converted into chemical energy during photosynthesis MORE

The light's energy raises the energy level of some chlorophyll electrons, freeing them from the chlorophyll molecules. Molecules of water (H2O) from the environment take part in chemical reactions in the cell. Electrons from the hydrogen atoms in each of these water molecules are attracted to the chlorophyll molecules lacking the electrons freed in step 1. More.

Plants usually convert light into chemical energy with a photosynthetic efficiency of 3-6%. Actual plants' photosynthetic efficiency varies with the frequency of the light being converted, light intensity, temperature and proportion of carbon dioxide in the atmosphere, and can vary from 0.1% to 8%.