Resistance: Ohm´s Law

References:
http://www.petervaldivia.com/technology/electricity/resistance-and-ohm-law.php


What is Electrical Resistance?
When electrons flow through a
bulb or another conductor, the
conductor does offers some
obstruction to the current. This
obstruction is called [b]electrical resistance.[/b]

* The longer the conductor
higher the resistance.
* The smaller its area the higher
its resistance

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 Ω

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. On the right, a
resistor used in the electronic industry.

Reading Resistor Values
The resistance of resistors is
indicated using colour-coded
bands on the body of the
resistor. The first three colour
bands indicate the value of the
resistor in Ohms. The first band tells us the first digit, the
second band tell us the second
digit and the third band tell us
the number of zeros