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Static electricity
Chapter summary 11. Charges on a conductor will distribute
themselves to reduce as much as
1. Static electricity is the accumulation possible the force of repulsion.
of excess electric charges in a region
that does not conduct electricity, 12. Hollow conductors have their excess
allowing the charge to remain in electrostatic charge distributed on
FOR ONLINE READING ONLY
place. their outer surfaces.
2. Every atom contains a positively 13. Lightning is a large discharge of
charged central part known as static electric charge within a cloud,
the nucleus, which attracts all the between two clouds or between a
electrons firmly to itself. There are cloud and the ground.
two types of charges: negative and
positive charges. Revision Exercise 1
3. An ebonite rod rubbed with fur 1. Choose the most correct answer in
becomes negatively charged. A items (a) to (e).
glass rod rubbed with silk becomes (a) Capacitors of 1 μF, 4 μF and
positively charged. 2 μF are connected in series.
4. The fundamental law of static Calculate the capacitance that
could replace them (equivalent
electricity states that like charges capacitance).
repel, unlike charges attract.
5. Conductors are materials with (i) 9 (ii) 4 µF
electrons that flow freely from atom 4 µF 7
to atom. Any excess charge on a 7 7
metallic conductor will distribute (iii) 4 µF (iv) 4 F
itself over the surface of the metal.
6. Insulators are materials that hinder (b) When a capacitor is charged
the free flow of charge. and disconnected from a battery,
7. Excess charge on an insulator will what will happen to its charge
and voltage if the distance
remain in the location where it was between the plates is increased?
introduced. (i) The charge will remain
8. Capacitors are devices for storing constant, but the voltage
charge. They are used in computers, will increase.
radios and other electronics. (ii) Both charge and voltage will
9. The SI unit of capacitance is the decrease.
Farad. (iii) The charge will decrease,
10. Charge is normally concentrated on but the voltage will remain
the sharp points of conductors. constant.
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Physics Form 2 Final.indd 35 25/10/2025 10:25
