(a) The first coloured band (1) gives the first significant figure, second coloured band (2) gives second significant figure, third coloured band represents multiplier (powers of ten) and the fourth coloured band gives the tolerance. Tolerance tells us how much variation can be there in the resistance value when put in use. If there is no fourth coloured band, the body colour should be considered as 20% tolerance. It means that the resistance value can vary by ± 20% of its value.
(b) Body of resistors may be big or small. If the body of a resistor is small, it is difficult to print the resistance value on it. Also, there should be a universally accepted standard for measuring resistance. Hence for convenience, colour coding system is used.
