Question

Why is it called a light reaction?

Answer 1

Light Reactions are a part of Photosynthesis.

Explanation:

Photosynthesis takes place in 2 stages: 1. Light Reactions 2. Dark Reactions.
These reactions are called Light Reactions because they take place only in the presence of Sun. These cannot occur in the abscence of Sunlight.
These were discovered by Robert Hill.