1) The unit of measure of the current is the Ampere (A). Since the current is defined as the amount of charge that passes a given point per unit time, 1 Ampere is defined as 1 Coulomb of charge per second:
[tex] 1 A=\frac{1 C}{1 s} [/tex]
2) The original term for "battery" was Voltaic pile. The Voltaic pile was the first electrical battery that could provide electric current to a circuit. It was invented by Alessandro Volta in 1799, and that is why it was originally called Voltaic pile.
3) The incandescent light bulb was invented in 1879 by Thomas Edison. The incandescent light bulb contains a wire filament that is heated when current passes through it; as the wire is heated, it gets hot and it emits radiation in form of light.
4) The fluorescent light bulb was invented in 1903 by Peter Copper Hewitt. It was a mercury vapor lamp, and it used to emit greenish light when current passed through it.
5) The SI unit for power is the Watt (W). As the power is defined as the amount of work done per unit time, one Watt corresponds to 1 Joule of work divided by 1 second:
[tex] 1W =\frac{1J}{1s} [/tex]
6) Voltage of the circuit
In this simple circuit, the resistance is [tex] R=25 \Omega [/tex], while the current passing through it is [tex] I=5 A [/tex]. Therefore, we can calculate the voltage in the circuit by applying Ohm's law:
[tex] V=RI=(25 \Omega)(5 A)=125 V [/tex]
7) Power in the circuit
Using the same circuit as before, with [tex] R=25 \Omega [/tex] and [tex] I=5 A [/tex], we can calculate the power of the circuit by using the following equation:
[tex] P=VI [/tex]
Since we calculate previously that V=125 V, we find
[tex] P=(125 V)(5 A)=625 W [/tex]
8) Kirchoff laws:
There are two Kirchoff laws:
1- Kirchoff current law - at each node of a circuit, the sum of the currents entering the node must be equal to the sum of the currents leaving the same node.
2- Kirchoff voltage law - for any closed loop in an electrical circuit, the algebraic sum of the potential differences must be equal to zero.
9) There are a lot of scientists which had a great impact on our life today, however since we are talking about the electricity, I would say Nikola Tesla. Tesla created the bases of the alternating current (AC) electric power systems that we use today in everyday life.
