The lamp that is lit radiates the heat and light energy.
The fragrance from the flowers, the burning of camphor give out chemical energy.
The effect of all these energies is activated by the positive energy that comes out of the idol. This is in addition to the north/south pole magnetic energy that is absorbed by the copper plate and utensils that are kept in the Moolasthan.
The water used for the Pooja is mixed with Cardamom, Benzoine, Holy Basil (Tulsi), Clove, etc is the "Theertham". This water becomes more energized because it receieves the positive-ness of all these energies combined.
The water that is sprinkled onto the people passes on the energy to all. That is the reason why, men are not allowed to wear shirts to the temple and ladies have to wear more ornaments because it is through these jewels (metal) that positive energy is absorbed in ladies. It is proved that Theertham is a very good blood purifier, as it is highly energized.