why in light reaction the amount of ATP IS MORE THAN NAD?

Answer 1

I think that science teachers generally do a bad job at explaining this. But plants undergo both photosynthesis AND cellular respiration. Remember, plants do not eat and thus must make the energy they need for cellular respiration. The process by which they make that energy is photosynthesis.

In the light reactions of photosynthesis, much ATP is used. Remember, the goal of photosynthesis is not to make ATP but to make glucose (C6H12O6). It is generally considered that the two processes, cellular respiration and photosynthesis, are the opposite of each other. For this reason the light reactions use much ATP.

NAD+ is used to carry electrons. Because the chloroplasts are making sugar there really is no need for NAD+ to be in as much abundance as ATP. Remember the rule of thumb, what happens in one process is the opposite in the other.