I am writing up a physics lab where we essentially submerged a light-bulb in a styrofoam cup of water and then calculated the electrical energy using the equation P=IV and then multiplied P by ∆time. Then we calculated the thermal energy using the equation Q=mc∆T. I understand you can find the electrical equivalent by dividing the electrical energy by the thermal energy, but I don't understand what the number for electrical energy actually is. Is electrical energy a constant that I am trying to prove in this experiment? Or is it the loss in energy from when energy is dissipated from the light-bulb to the water? Or is it something else?