M3.2 Flashcards
(26 cards)
What is static electricity?
Static electricity is when positive and negative charges are unevenly distributed, leaving materials with an overall positive or negative charge.
How is static electricity generated?
This can be achieved by contact, friction or induction, for example rubbing two materials together will move some electrons from one material to the other, changing the distribution of charge.
What are the electrostatic laws?
Opposite charges attract, like charges repel.
What does Coulomb’s Law state?
The magnitude of the electrostatic force of attraction, or repulsion, between two-point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.
What type of solid is a good conductor?
Metal
Why is electricity conducted well in a metal?
A high number of free electrons(And high electron mobility)
What is the movement of electrons known as?
Electric current
What happens when a conductor narrow?
Electrons move at a higher speed in order to keep current constant, which leads to greater heating
How does cross-sectional area affect the rate of flow of electrons when current is constant?
It doesn’t
Is water a good conductor?
No, ordinarily it is a poor conductor, however understand the right circumstances it conducts electricity well.
What happens when a DC current passes through water?
The water decomposes into hydrogen and oxygen?
What is the process of passing an electric current through a liquid to decompose chemical compounds is known as what?
Electrolysis
What is the ration of hydrogen gas produced the negative pole in electrolysis?
2/3 of gas produced
Is hydrogen produced at the anode or cathode?
Cathode
What is the ratio of oxygen produced at the positive pole in electrolysis?
1/3 of total gas produced
What can be added to water to make it a better conductor?
Acids, bases or salts
What is the conducting substance in electrolysis known as?
Electrolyte
Do cations flow towards the anode of cathode?
Cathode
What is it known as when a current is applied across a low pressure gas?
Gas discharge
What is applying a current across a low pressure gas often accompanied by?
The emission of visible light
What gases emit characteristic colours when a current is applied across it?
Neon, Helium
How are charge carriers(electrons and gas ions) generated in a gas?
External energy supply such as heat, light and radioactivity
What happens to the charge carriers in a gas?
- Reach high speeds due to low pressure and high pd
- Electrons collide with gas atoms resulting in more electrons, known as “electron cascade”
- Charge carries eventually lose energy in form of electromagnetic radiation(some of which is light)
- Some charge carriers reach the end of the tube,meaning that current is flowing
How if electricity conducted in a vacuum?
Charge carriers are emitted by objects such as stars, or as simple as a heated cathode, which move through what would otherwise be a vacuum
