Q3.
1.
A pupil did an experiment following the instructions below.
Take a polythene rod (AB), hold it at its centre and rub both ends with a cloth.
2.
Suspend the rod, without touching the ends, from a stand using a stirrup and nylon thread.
3.
Take a perspex rod (CD) and rub it with another cloth,
4.
Without touching the ends of the perspex rod bring each end of the perspex rod up to, but
without touching, each end of the polythene rod.
5.
Make notes on what is observed.
The diagram below shows how the apparatus is to be set up.
(a) When end C was brought near to end B they attracted each other.
(i) Explain why they attracted each other.
(ii) What would happen if end C were brought near end A?
(b) The experiment was repeated wiin two polythene rods.
(i) Describe what you would expect the pupil to observe as the end of one rod was
brought near to the end of the other.
(ii) Explain your answer.
(c) Explain, in terms of electron movement, what happened as the rods were rubbed with
the cloths.
