When a plastic comb is rubbed with dry hair, it acquires some charges due to which it attracts tiny pieces of paper. But when a plastic comb is rubbed with wet or oiled hair the same does not happen. Why?
When a plastic comb is rubbed with dry hair, it acquires some charges due to which it attracts tiny pieces of paper. But when a plastic comb is rubbed with wet or oiled hair the same does not happen. Why?
When a plastic comb is rubbed with dry hair, there is a transfer of loosely held electrons in our hair to comb by means of friction. In this particular case, the plastic comb acquires negative charge due to its tendency to acquire electrons. Thus Buildup of static charge takes place. So, hair becomes positively charged as it loses electrons and the comb acquires a negative charge. This negatively charged comb can now attract objects that carry an excess of positive charge in them, like bits of paper or dust particles.
But incase of wet or oiled hair has a coating of water or oil on them, which reduces the friction between the hair and comb when we run it through hair and as a result no electron flow takes place. Thus no static charges develop. The comb would never get negatively charged and consequently wouldn't attract any paper pieces etc.
When a plastic comb is rubbed with dry hair, there is a transfer of loosely held electrons in our hair to comb by means of friction. In this particular case, the plastic comb acquires negative charge due to its tendency to acquire electrons. Thus Buildup of static charge takes place. So, hair becomes positively charged as it loses electrons and the comb acquires a negative charge. This negatively charged comb can now attract objects that carry an excess of positive charge in them, like bits of paper or dust particles.
But incase of wet or oiled hair has a coating of water or oil on them, which reduces the friction between the hair and comb when we run it through hair and as a result no electron flow takes place. Thus no static charges develop. The comb would never get negatively charged and consequently wouldn't attract any paper pieces etc.
