P2 Topic 1 - Electrostatics

Question 0

How is electrostatics used in photocopiers?

Answer 0

1. Original document
2. Image of doc. projected onto +ve copying plate
3. Light hits plate and charge leaks away
4. -ve charged black ink is attracted to +ve areas
5. Paper placed on top
6. Photocopy removed off copying plate

Question 1

How is static formed?

Answer 1

Friction between two objects that either give away or take in electrons easily.

Question 2

Equation Triangles

• Coulombs 1
• Coulombs 2
• Voltage
• Power
• Energy 1
• Energy 2

Answer 2

Coulombs = Current x Time
Coulombs = No. of electrons x Charge of each electron
Voltage = Current x Resistance
Power = Voltage x Current
Energy = Power x Time
Energy = Voltage x Coulombs

Question 3

What is a diode?

Answer 3

A diode is a device that only lets the current in a circuit go one way.

Question 4

Give uses of electrostatics

Answer 4

Paint sprayers - paint positively charged and body to be painted charged negatively

Lightning

Question 5

What is earthing?

Answer 5

Having a metal conductor from object to ground to transfer electrons from one to the other.

Used when refuelling planes or gas stations and in tall buildings.

Question 6

What decides where the electrons go when two or more objects are rubbed together?

Answer 6

Electron affinity, or how easily a material gives away its electrons, decides where the electrons go. The material with a higher affinity will become negative as it takes on electrons, while the material with the lower affinity, will become positive as it loses electrons.