Electrostatic Energy

Question 0

How does something get an induced charge?

Answer 0

If the other object is positive, the electrons will all move to the surface to give the object a negative charge to attract to the other object.
If the other object is negative, the electrons will all move away from the surface down into the object, giving the object a positive charge to attract to the other object

Question 1

What do like and different charges do?

Answer 1

Like charges repel and different charges attract.

Question 2

How does earthing make negative objects neutral?

Answer 2

The surplus electrons will move into the ground, rendering the object neutral.

Question 3

How does earthing make positive objects neutral?

Answer 3

Electrons will come up into the object from the ground, to neutralise the protons.

Question 4

How do sparks happen?

Answer 4

They happen when an object has enough charge that it can discharge, causing the air to conduct and produce a spark.

Question 5

How are sparks a danger when refuelling?

Answer 5

The petrol rubs against the rubber tube, which produces a spark which could make the petrol explode, as it is flammable. To prevent this, planes have a grounding wire to attach it to the ground.

Question 6

How does the electrostatic precipitator work?

Answer 6

1- the dust and waste gases pass through the charged grid, meaning it gets a static charge.
2- the earthed collecting plates are given an induced charge, so they can attract the oppositely charged dust.

Question 7

How does spray painting work?

Answer 7

Drops of paint are given a static charged, and shot at an object which is grounded, so it becomes oppositely charged. The droplets are then attracted to the object, producing a more even finish, and wasting less paint.

Question 8

How does a photocopier work?

Answer 8

The image of the document is projected onto a positively charged copying plate. Where light falls onto the plate, charge leaks away. Negatively charged toner particles are then attracted to the positive areas. Paper is then placed on top, and heat applied to make the toner stick.

Question 9

What is an experiment to show how insulating materials can be charged by friction?

Answer 9

• get polyethene rod and hover over small bits of paper. Will have no effect
• rub the polyethene rod with a cloth, and hover over pieces of paper. They will be attracted to it because the rod has now become charged due to rubbing w cloth