Empty lamp

Solution in terms of energy

If, in Physics, something is reasoned related to energy, to explain facts, it is of particular importance to pay attention to the priciple of conservation of energy. According to it, the amount of energy of a system (in this case the lamp with its battery, the light bulb and the surroundings) does not in- or decrease. Energy is never used up.

Instead of this, one says that energy changes its state: It is transformed. In this case, there is a potential in terms of the substances in the battery to react together, if they are connected by a circuit. Therefore, there is a certain amount of chemical energy stored in the battery. This energy is then utilised by the lamp by transforming it into light and heating energy in the light bulb.
The chemical energy does neither dissolve nor is it used up, but it is transformed into other forms of energy.