Resistance

The electrical resistance of an electrical element is the opposition to the passage of an electric current through that element. resistor is actually the conductor(in which the electric current flow is called conductor). there is free electron present in the conductor when the electron in the current passed into the conductor the electron present into the conductor which is freely move is strike and reduce the speed of electrons and in this way resistor drop the current speed.
The si unit of resistance is called ohm Ω.
                                                         if we increase the temperature of conductor. the free electron in the conductor move rapidly and the chance of collision increases is also increase and resistance value is large. if we decrease the temperature resistance value is also decreased. this is the simpler concept of resistance in otherwords we can says that resistance is the material which decrease the speed of current. the speed of current is due to the voltage (electromotive force) the resistor drop the voltage.
                                                         the difference between voltage and electromotive force is that when the voltage source is not connected to the circuit the force appear to its terminal is called electromotive force. when the source connected in the circuit is called voltage  

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