Electrical energy is derived from the electric potential energy. It is the energy that have been obtained from transforming the electric potential energy. In a more elaborate manner, we can say that electrical energy is energy caused by electric charges in motion.
The electrical energy is provided by the electric current and the electric potential of an electric circuit. When the electrical potential energy gets converted to another form of energy, it ceases to be electrical potential energy and it can attain the form of heat, motion and light among many other forms.
It is interesting to note that the final step of generating the electrical energy is usually the same notwithstanding the form of energy that is started with. For instance, in some cases, nuclear energy is the starting form of energy and the nuclear energy is used to produce steam by heating water. The steam is in turn used to rotate a turbine of an electrical generator that generates electrical energy. The same is the case with the hydroelectric power generation where water falling from a height is used to rotate a turbine of an electrical generator which in turn generates electrical energy. If the wind energy is the starting form of energy, the wind turns a turbine of an electrical generator which then generates electrical energy.
The electrical energy is the one that brings about the electrical power.
As we have learnt during our H2 Physics tuition classes, the instantaneous electrical power can be mathematically represented as:
P (t) = V (t) . I (t)
Where P (t) = the instantaneous power, V (t) = the potential difference, I (t) = the current
If a resistor with a voltage (that doesn’t vary with time) to current ratio, is the one under consideration, then:
P = V I = V2 / R = I2 R
Where R is the resistance measured in ohms. And the R can also be calculated as shown below:
R = V / I
Instances where Electrical Energy is used
1. In vehicles (cars) there is a chemical reaction in the battery which produces an electric current. The moving charges in the current results to electrical energy, which is then used to ignite the car, light the lamps, turn the fun among other things.
2. Electrical energy is the key behind the functioning of most of the electronic gadgets that we use; for example the mobile phones, personal computers and calculators just to mention a few.
3. Electrical energy is also used in lighting thousands if not millions of households around the world at night.