What are the reactants and products of the light reaction?s in photosynthesis?

It actually photosynthesises to give us oxygen and also it absorbs light.

Heres the site
http://www.bbc.co.uk/schools/ks3bitesize/science/biology/green_plants_1.shtml

Step 1: Photosystems
   Diagram showing the two photosystems in the light-depend reaction. (In link).
The light-dependent portion of photosynthesis is carried out by two consecutive photosystems (photosystem I and photosystem II) in the thylakoid membrane of the chloroplasts. The photosystems are driven by the excited chlorophyll molecules.

To begin photosynthesis, the chlorophyll molecule in photosystem II is excited by sunlight and the energy produced helps to break down a water molecule (H2O) into ½O2 (with electrons removed) and 2H+. The removed electrons are excited by the light energy. When the electrons prepare to come to their rest state, they go through an oxidative phosphorylation process and produces an ATP molecule.

As the electrons are coming to a resting state, they are excited again in photosystem I and raised to a even higher energy state. The excited electrons are then used to produce NADP+ + H+. The highly energetic NADPH molecule is then fed into the Calvin Cycle to conduct carbon fixation.
In summary ATP,O2 and NADPH are the products.
H2O,NADP,ADP and Pi are the reactants.

The balanced equation for photosynthesis is:

6CO2 + 6H2O + Energy ® C6H12O6  + 6O2

In other words, carbon dioxide plus water plus light energy from the sun react to form glucose (C6H12O6) and oxygen.

This is the exact OPPOSITE of the equation for cellular respiration, which occurs in mammals, etc.

The light reaction occurs in the thylakoid membrane, and end up producing adenosine triphosphate (ATP) and NADPH. These are needed for the light-independent reactions which produce glucose.

Here is a diagram that shows it:

http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20101/Bio%20101%20Lectures/photosynthesis/photos4.gif