Light or solar energy can be used to speed up a chemical reaction. Benzene is not brominated with or without light. The methyl group on the toluene is brominated. Beware Bromine is an extremely strong oxidizer and will burn skin terribly. Wear gloves and goggles and prepare the bromine solution in a hood.
Bromine vapors are dangerous.
Keep bromine solution covered during demonstration. The Sodium Thiosulfate solution should be used to neutralize bromine. Neutralize any spills of bromine immediately and rinse any glassware that held bromine with the Sodium Thiosulfate solution. Glacial Acetic Acid is concentrated and will irritate skin. Wear gloves and safety goggles.