Electrical energy is useful to us because it can be converted into other forms of energy. In the power tools such as electric heaters, electric stoves, and air conditioning, electrical energy is converted into heat energy in the wire barriers known as “heating elements”. Then, in a lot of light (Figure 7.4), a small wire filament becomes so hot that it shines. Only a few percent of the electrical energy is converted into visible light, and the rest more than 90% into heat energy.
Pictures 1:20 filament wire convert electrical energy into light
Electrical energy can be converted into heat energy or light on power tools, because the flow is usually rather large, and a lot of collisions between electrons and atoms in the wire. At each collision, a transfer of energy from electrons to atoms ground it, so that the kinetic energy of atoms increases and causes higher temperature wire elements. If you attend an electric iron which is connected to the source voltage, it is not how long it will be hot.
This happens because of the effort to move the electric charge at any time in the electrical circuit that is equal to the electrical energy is converted into heat energy. The amount of energy per unit of time is called power. The power is converted by the electrical equipment is energy that changed when the charge Q moving across a potential difference of V. electrical power is the rate of change of energy per unit time, formulated:
Charge flowing per unit time Q / t is an electric current, I, so we get:
The above equation shows that the generated power can be changed by a device for the value of the current I passing through and the potential difference V between the ends of the conductor. The SI unit of electrical power is a watt (1 W = 1 J / s). Power or rate of change of energy on resistance R can be written based on Ohm’s Law as follows: According to Ohm’s Law the power equation can be written:
Description:
P: power (W)
W: electrical energy (J)
V: power supply voltage (V)
I: strong electric current (A)
R: electrical resistance (Ω)