A: There is no NOT gate NOT is a term used to signify that the function is negated like OR becomes NOT if the output is negated by an inversion of the final signal. The difference in gates OR and NOR...
its bcoz all other gates lik AND,OR,NOT,XOR...........etc.u can achieve the functionality of these gates with the help of NAND and NOR.u can replace all these gates in a circuit wit the help of NAND...