Electric Charge (electrostatic)

Question 1

What are electrical insulators (+ examples)

Answer 1

Materials that don’t conduct electricity

E.g. Plastic, hair, jumper

Question 2

What are electrical conductors (+ examples)

Answer 2

Materials that conduct electricity

E.g. Metals

Question 3

What causes insulating materials to be charged

Answer 3

Friction

Question 4

How do insulating materials get charged using the example of hair and a balloon

Answer 4

Rubbing hair and the balloon together causes electrons to transfer from one object to another so one object (the hair) is positively charged and the other object (the balloon) becomes negatively charged

Question 5

Why does the hair stand on end after being rubbed by the balloon

Answer 5

The hair and the balloon are oppositely charged so the hair is trying to get as close to the hair as possible as opposite charged attract

The hairs are the same charge so they try to repel against each other and get as far away from each other as possible

Question 6

Why would the hair and balloon stick together after rubbing on each other

Answer 6

The hair is positively charged and the balloon is negatively charged so they stick together as opposite charges attract

Question 7

What does a neutral object have

Answer 7

Equal amounts of positive and negative changes on it

Question 8

What do charged objects have? Why?

Answer 8

There is an imbalance of positives and negatives. This is because the object has lost or gained electrons

Question 9

What needs to happen to rebalance the charge

Answer 9

Have to neutralise the object by either restoring electrons or removing electrons

Question 10

How do we neutralise an object? What is the process?

Answer 10

Earthing/ grounding

Connecting the charged object with a conductor (as it lets electrons flow along it easily) to a large source of electrons, usually the ground.

Question 11

What happens when neutralising a positive object

Answer 11

The electrons from the ground flow to the positive object so it gains electrons and becomes neutral

Question 12

What happens when neutralising a negative object

Answer 12

The electrons from the object flow to the ground so it loses electrons and becomes neutral

Question 13

What is polarisation

Answer 13

The separation of positive and negative charges in an overall neutral object. This object is said to be polarised

Question 14

What happens to the charges in a wall as a negatively charged balloon moves towards it

Answer 14

The negative balloon is attracted to the positive charges in the wall. The negative electrons in the wall repel against the negative balloon so the charges in the wall separate making the wall polarised

Question 15

Why might it be dangerous to refuel a plane and what can be done to prevent the dangers

Answer 15

Friction between the air molecules and the plane causes the plane to be charged. The charged plane could cause an explosion when refuelling

To prevent this we need to ground the plane by connecting the plane with the ground with a conductor so the charge can be neutralised

Question 16

Why might it be dangerous to fill a a storage tank with fuel and how can we prevent this

Answer 16

The friction between the fuel and the fuel pipe causes the tanker to become charged. The charged tanker could cause an explosion

To prevent this we need to ground the tanker by connecting it with a conductor to the ground to neutralise it

Question 17

What is a use of electrostatic charges and how does it work (5 steps)

Answer 17

Photocopiers

In the photocopier a light sensitive plate is negatively charged

An image of the document projects onto the plate, the bright areas lose their charge and the dark areas keep it

Positive powdered ink is attracted to the dark areas which were still negative

A blank sheet of paper is pressed against the plate and picks up the powered ink

The paper is heated so the powered ink melts and sticks to the paper