IGCSE Physics\Electrostatics\Important Concepts
IGCSE PHYSICS
ELECTROSTATICS: IMPORTANT CONCEPTS
CHARGED PARTICLES, CONDUCTORS AND INSULATORS
Objects are neutral because there are equal numbers of positive charges and
negative charges in the object.
Principle of conservation of charges: charges can neither be created nor destroyed,
but they can be transferred from one object to another.
When an object loses negative charges (electrons), it becomes positively charged; if
the object gains negative charges, it becomes negatively charged.
Principle of electrostatics:
Like charges repel
Unlike charges attract
Conductors are materials that allow electric charges to flow through them easily due
to presence of freely moving electrons; electrons are able to redistribute themselves
freely throughout the object.
Insulators are materials that do not allow electric charges to flow through them
easily due to absence of freely moving electrons; electrons gained remain at the
surface at the region where the object is charged.
Test Yourself:
1. You are given a piece of material who could be an electrical conductor or an
insulator. Describe a simple experiment to identify whether the given material is a
conductor or an insulator.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
2. The figure shows a positively charged metal
sphere coated with conducting paint suspended
near a negatively charged plate. The sphere is insulating
string
seen to be displaced towards the negative plate
until it touches the plate, after which it returns to
its original position.
(a) Explain the observation above. positively negatively
charged charged
_____________________________________ metal plate
sphere
_____________________________________
_____________________________________
_____________________________________
_____________________________________
_____________________________________
______________________________________________________________________________
Nakazawa EduServ. Created by Jackson Tik, B.Sc. (NUS). ©All rights reserved.
1
IGCSE PHYSICS
ELECTROSTATICS: IMPORTANT CONCEPTS
CHARGED PARTICLES, CONDUCTORS AND INSULATORS
Objects are neutral because there are equal numbers of positive charges and
negative charges in the object.
Principle of conservation of charges: charges can neither be created nor destroyed,
but they can be transferred from one object to another.
When an object loses negative charges (electrons), it becomes positively charged; if
the object gains negative charges, it becomes negatively charged.
Principle of electrostatics:
Like charges repel
Unlike charges attract
Conductors are materials that allow electric charges to flow through them easily due
to presence of freely moving electrons; electrons are able to redistribute themselves
freely throughout the object.
Insulators are materials that do not allow electric charges to flow through them
easily due to absence of freely moving electrons; electrons gained remain at the
surface at the region where the object is charged.
Test Yourself:
1. You are given a piece of material who could be an electrical conductor or an
insulator. Describe a simple experiment to identify whether the given material is a
conductor or an insulator.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
2. The figure shows a positively charged metal
sphere coated with conducting paint suspended
near a negatively charged plate. The sphere is insulating
string
seen to be displaced towards the negative plate
until it touches the plate, after which it returns to
its original position.
(a) Explain the observation above. positively negatively
charged charged
_____________________________________ metal plate
sphere
_____________________________________
_____________________________________
_____________________________________
_____________________________________
_____________________________________
______________________________________________________________________________
Nakazawa EduServ. Created by Jackson Tik, B.Sc. (NUS). ©All rights reserved.
1
