Question

metal rod rubbed with wool charge is not produced why??

Answer 1

You can not statically charge a piece of iron because in an iron rod any electric charges do not stick to the location where you put them. They will flow away, e.g. into your hand.

If you rub two different isolating materials against each other, the electrons on the surface will redistribute until there is an equilibrium, and often the result is an uneven distribution over the two leaving one positively and the other negatively charged.

Answer 2

For instance, the outer electrons of the atoms in wool are held more loosely than the outer electrons of the atoms in a plastic ruler. ... If a rod made of Perspex is rubbed on a cotton cloth, an electric charge is also produced on the rod.