B. explain how is light energy converted
into chemical energy during photosynthesis?

Light energy absorbed by pigments produces high-energy electrons that are used to convert NADP+ ( a coenzyme that functions as a universal electron carrier, accepting electrons and hydrogen atoms to form NADPH) and ADP (  adenosine diphosphate which helps in formation of the energy) to the compounds NADPH and ATP (energy), trapping the energy in chemical form.

Explanation:

During the process of photosynthesis, light penetrates the cell and passes into the chloroplast. The light energy is intercepted by chlorophyll molecules on the granal stacks. Some of the light energy is converted to chemical energy. During this process, a phosphate is added to a molecule to cause the formation of ATP. The third phosphate chemical bond contains the new chemical energy.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link: