11 Flashcards Preview

Physics > 11 > Flashcards

Flashcards in 11 Deck (14)
Loading flashcards...
1

How does static get (created)

- 2 insulators or insulated objects rub together with friction.
- during this the electrons from one material move to another.
- one gains electrons and then has a negative charge if it loses then it has a positive.
- Finally, when a conductor comes near the charge passes onto that object and the charge gets earthed.

2

What is an example of induced charge?

Sticking a charged ballon against the wall.

3

How do charged balloons stick to walls?

Were a positive charged balloon goes up against the wall, all the negative ions in the wall go to the outer layer of the wall and all the positive ions repel and go further into the wall. This attraction keeps the balloon on the wall.

4

Dangers of static electricity:

- lightning
- the actual shock.
- the shock or jump of a spark of electricity can light flammable substances.

5

What is ‘earthing’

Connecting things to the ground.

6

Why do we need earthing?

To stop insulators getting static charge,
This stops sparks for occurring which could cause a fire or a danger hazard.

7

How does lightning work?

- when water vapour rises to form clouds, positive and negative ions separates as the positive ions are lighter.
- when the charge from the clouds get close to the earth the spark goes off.

8

How do Electrostatic sprayers work?

The paint particles are charged before the car is to be sprayed as they are put through pipes where they rub against insulators so electrons can transfer to the paint dust.
- Then they are sprayed they are attracted to the car as its a conductor and is earthed, so it goes on the car, It also spreads out as the paint repels each other coming out of the nossle spreading it out.

9

Why do we make fuel a conductor?

So when they travel in lorry’s they conduct to stop the build up of static charge which could stop any sparks of electricity which could cause the flammable fuel to set alight.

10

What is meant by Electrical field strength ?

It’s electrical force per unit of charge.

11

What is an electrical field?

An area around a charge which an object with charge is effected. And would feel a force.

12

Electrical field strength =

Force / charge.

13

Always draw diagrams with arrows:

From + to -.
Or
From north to south.

14

Comparison of gravitation and electrical fields:

- both non contact forces.
- gravitation effected by mass.
- electrical effected by charge.
- only electrical can repel and give out an operative force.