How to identify electrolyte and photo decomposition reactions?

Photo decomposition is a chemical reaction in which a substance is broken down into simple substances by exposure to light (photons). 

Eg: Breaking of silver chloride into silver and chloride in the presence of sunlight.

Electrolytic Decomposition means the compound decomposes or breaks up in ions when electricity is passed in a solution.

Eg: When we pass electricity in a solution of Na-Cl and water NaCl is broken in ions.

Electrolysis of water is the decomposition of water into oxygen and hydrogen gas due to an electric current being passed through the water.