Static Electricity Flashcards
SI Unit of Electric Charge
Coulomb (C)
Charge of 1 electron/proton
1.6 × 10⁻¹⁹ C
How do like and unlike charges react with one another?
Like charges repel, unlike charges attract
What is an Electric Force?
When an electric charge exerts a force on another nearby charge
Properties of an electric force
Can be attractive/repulsive
Gets weaker with distance
What is a Electric Field?
The region where an electric charge experiences an electric force
Electric field of positive charge
Lines go out
Electric field of negative charge
Lines go in
Electrostatic Charging due to Friction
When rubbed, surface atoms are disturbed. Some electrons from surface of one object travel to the other. Object losing electrons becomes positively charged. Object gaining electrons becomes negatively charged. Electrons are easily removed and added to an atom by friction as they are weakly bounded to the atom
Examples of materials with positive charges
Glass, wool, hair, Perspex
Examples of materials with negative charges
Silk, Polythene, Rubber, Wool
What are Conductors?
Materials that have free electrons and are able to conduct electricity (not easily charged by rubbing silk/fur)
What are Insulators?
Materials that do no have free electrons and cannot conduct electricity (electrons are confined at region of rubbing)
Discharging charged insulators and conductors
Earthing
How to discharge a charged insulator?
Heating. Intense heat causes air surrounding insulator to be ionised. These ions in air then neutralise excess charges in insulator
Humid conditions also neutralise a charged insulator over time as water vapour in air helps remove excess charges