STATIC ELECTRICITY

Question 1

What is a conductor?

Answer 1

Has delocalised electrons that flow freely.

Question 2

What is an insulator?

Answer 2

Has localised electrons that are held tightly in place.

Question 3

Name two examples of conductors:

Answer 3

gold, copper

Question 4

Name two examples of insulators:

Answer 4

rubber, wood, plastic

Question 5

What is charging by friction?

Answer 5

Applying a frictional force between two insulators, transferring electrons, giving a ‘permanent’ charge.

Question 6

What is charging by induction?

Answer 6

Bringing another charged object close to an insulator to create a ‘temporary charge’.

Question 7

Why do the electrons transfer when charging by friction?

Answer 7

Because they are lightest and have the shortest distance to travel.

Question 8

Explain how the insulators have become charged (3).

Answer 8

1. The insulators have become charged by friction
2. The electrons have been transferred
3. From rod to cloth

Question 9

What does charging by induction NOT involve?

Answer 9

Transfer of electrons

Question 10

Describe what happens if a negatively charged balloon is held up to a wall:

Answer 10

As the balloon moves closer to the wall, the electrons inside the wall are repelled creative a positive surface closest to the balloon and a force of attraction.

Question 11

Describe what happens when a positively charged balloon is moved towards the wall:

Answer 11

the electron in the wall would move towards the the balloon as they are attracted and move to the closest surface. This means that the surface of the wall becomes negatively charged and attracts the balloon.

Question 12

How does a Van de Graaff generator build up charge?

Answer 12

The generator rubs plastic and rubber together to produce a charge on the belt which is then transferred via a cone onto the conductor dome to produce a charged dome.

Question 13

How does spray painting of cars using static electricity work?

Answer 13

The vehicle is grounded and given a positive charge whilst the paint is given a negative charge. They attract each other, creating an even coat.

Question 14

What are the benefits of using static electricity to spray paint cars?

Answer 14

Paint droplets repel each other and are attracted to car creating even coat.
East to pain odd objects.
Less waste of paint.

Question 15

What is the function of a dust precipitator?

Answer 15

To remove pollutants from the air.

Question 16

How do dust precipitators work?

Answer 16

1. smoke travels up precipitator and travels past strongly charged grid that causes particles to have a negative charge
2. Further up the precipitator, positively charged plates attract the charged pollutants and collect them in collecting plates.

Question 17

What are the dangers of electrostatics and planes.

Answer 17

It can cause sparks which can then cause fires and explosions.

Question 18

How could charge build up on a plane?

Answer 18

Friction from air resistance causes them to become statically charged

Question 19

Why is an earthing wire important when re-fuelling?

Answer 19

A copper wire can provide a low resistance path for the charge to travel to the ground and leave the plane.