SP11 - Static Electricity ✓ Flashcards Preview

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Flashcards in SP11 - Static Electricity ✓ Deck (20)
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SP11a - Describe the movement of electrons and the charges involved when you rub an acetate rod with a cloth.

  • Both objects start off as neutral.
  • Electrons move from the acetate rod to the cloth so the acetate rod ends up positive and the cloth ends up negative.


SP11a - Describe the movement of electrons and the charges involved when you rub an polythene rod with a cloth.

  • Both objects start off as neutral.
  • Electrons move to the polythene rod from the cloth so the polythene rod ends up negative and the cloth ends up positive.


SP11a - Describe what will happen when you hang two rods next to each other with:

  • Positive and positive charges
  • Positive and negative charges
  • Negative and negative charges

  • Repel
  • Attract
  • Repel


SP11a - Explain how charging with induction works. (Use a balloon a jumper and a wall as an example)

  • If you rub a balloon against a jumper, the friction causes electrons to transfer from the jumper to the balloon.
  • The balloon now has a negative charge
  • When brought close to a wall, the negative charge of the balloon repels the electrons in the wall
  • The protons are brought closer to the surface of the wall as they are attracted to the balloons negative charge
  • The balloon is attracted to the positive charge on the surface of the wall causing it to stick
  • The wall has an induced charge


SP11b - How might you become charged while walking along a carpet?

Friction between your feet and the floor and slight friction between you and the air builds up charges.


SP11b - After gathering charge, how may you become discharged?

  • By touching something made of conducting material, the electrons will jump to the object and head to the ground.
  • You may experience a small electric shock


SP11b - Explain how lightning occurs.

  • Static electricity builds up in clouds due to friction between ice and water particles in air currents.
  • The negatively charged particle move towards the bottom of the cloud.
  • As the ground is neutral, it is relatively positive to the cloud and so when the charge in the clouds is too great, they jump to the ground to discharge.
  • This produces a spark which is lightning.


SP11b - How may a tall building protect an area from lightning.

  • A tall building may install a lightning conductor.
  • This would be a metal structure that would be the tallest structure in an area that runs through the centre of the building to the ground.
  • This means that a cloud will discharge through this which wont affect the surrounding areas.


SP11b - Explain the safety feature that protects airline tankers and aircrafts.

  • As high amounts of fuel pass through the nozzle at a fast rate, this build up friction which charges the fuel droplets.
  • Once they have built up a great charge they want to discharge.
  • This would create a spark which would light the fuel causing an explosion.
  • The bonding line is attached which earths the aircraft so that the charge flows through easily to the ground without any spark.


SP11b - Why don't cars need a bonding line at petrol stations.

The pipes and the car's tyres earth the car already.


SP11b - Name some uses of static electricity.

  • Electrostatic sprays:
    • Spray paint
    • Pesticide
  • Printers
  • Electrostatic precipitators


SP11b - How do electrostatic sprays work?

The nozzle contains electrodes which negatively charge the spray droplets. This leads to two things:

  1. The like charge between all droplets spread them out
  2. The negative charge attracts to the relatively positive object/crop and then charges it by induction to stick


SP11b - Name some advantages of electrostatic sprays

  • Since they spread out there is wide coverage
  • Since they attach through static induction there is even coverage
  • Since all the droplets attach, less spray is wasted


SP11c - What is a force field, and what is an electrostatic field?

  • A force field is the area around an object in which an object will experience a force and so...
  • An electrostatic field is the area around an object where a charged object will experience a force


SP11c - What does a negative and a positive point charge diagram look like

  • Both are a dot with equally spaced lines originating form the centre.
  • In a positive one there are arrows away and in a negative one they are towards


SP11c - What will be the difference between two field diagrams if one has a stronger charge

There will be more lines as they will be closer together


SP11c How do you know where the field is strongest?

Where the lines are closest together


SP11c - What are the four rules about field lines?

  • Lines never cross
  • The closer the lines are is where the field is strongest
  • Start on the positive charge and end on the negative charge
  • Shows the direction of force on an object


SP11c - What do two oppositely charged parallel plates form?

A uniform parallel electrostatic field


SP11c - If an alpha particle is placed into a uniform parallel field where will it move?

Towards the negatively charged plate.