The Cold War, refers to the war between the United States and Russia. China could also be included in the definition. The Cold War, asâ¦ noted, existed because of differing political ideologies between the two powers. Basically, it was the Western Ideals of democracy against the Eastern communists.
Every material has an electrical resistance and it is the reason that the conductor give out heat when the current passes through it. Resistance is a measure of how much an object opposes the passage of electrons. The unit of electrical resistance is the ohm and it is represented by Ï. Every material has Resistance. Copper has a low resistance and wood has a high resistance. For example, a metre of copper has a resistance of only 1 Ohm but a metre of wood has a resistance of 10000000 ohm. We need resistance to reduce the flow of electrons through a circuit, so we can build resistors to behave as Electrical resistance.
The SI unit for measuring an electric current is the ampere, which is the flow of electric charge across a surface at the rate of one coulomb per second. Electric current is measured using a device called an ammeter. Electric currents cause Joule heating, which creates light in incandescent light bulbs.