Topic 11- Static Electricity

Question 1

What has charges?

Answer 1

All property of matter

Question 2

What do like charges do?
What do opposite charges do?

Answer 2

Like charges attract
Opposites reppel

Question 3

Can insulators conduct electricity? Why?

Answer 3

-insulators can’t conduct electricity
-their electrons cannot flow throughout the material, They’re fixed

Question 4

Can conductors conduct electricity? Why?

Answer 4

Conductors can conduct electricity

-their elections can flow, they’re delocalised

Question 5

Can insulators become CHARGED? How?

Answer 5

-Insulators become charged by friction when 2 insulators are rubbed together. Electros are transfered from one object to another forming a positive charge on one and a negative charge on the other.

Question 6

Why do conductors not become charged when rubbed together?

Answer 6

Because electrons can flow in and out of them , cancelling out any effect so they stay neutral

Question 7

How is a positive static charge formed? Negative?
What decides which object looses/ gains electrons?

Answer 7

A positive static charge is formed when an object looses electrons

Negative static charged formed when an object gains electrons

The material decides what object looses / gains electrons

Question 8

When does sparking occur? What is sparking?

Answer 8

Sparking occurs when enough charge builds up between two objects that are close but not touching

The spark is when the charge jumps through the air from the highly negative object to the highly positive object , balancing the charge

Question 9

What force do charged objects experience?

Answer 9

Electrostatic force

Question 10

How is the electrostatic force increased?

Answer 10

By greater charge
By putting objects closer together

Question 11

Is the electrostatic force contact or non contact

Answer 11

Non contact

Question 12

How does a baloon stick to the wall?

Answer 12

A positively charged balloon next to a wall attracts electrons in the wall , the induction causes the balloon to stick to the wall

Question 13

Uses of static electricity …

Answer 13

-photocopiers use static electricity to copy images onto a charged plate before printing them

-used to reduce dust and smoke that comes from industrial chimneys

-electrostatic sprays

Question 14

What are electrostatic sprayers used for? How does it work? Advantages

Answer 14

-used to give a fine even coat of spray (bikes, cars)

1)spray gun is charged (charges up small droplets of paint) each paint drop repels Eachober as they have the same charge , so you get a fine even spray

2)object getting painted is given opposite charge to the gun, this attracts the spray

-this gives an even coat
-hardly any spray is wasted
-parts of the bike/ car pointing away will still receive paint

Question 15

What’s earthing?

Answer 15

A process that allows electrons to flow to the earth, removing excess charge

Question 16

How does too much static cause sparks? Example ..

Answer 16

1)As the electric charge builds up on an object , potential difference increases between object and earth

2) if potential difference gets high enoguh , electrons can jump across the gap (this is the spark)

3)they can also jump to any earhed conductor nearby

• lightining

Question 17

Real life examples of the dangers of static electricity …

Answer 17

Refuelling cars- as fuel flows from pipe into tanker , static builds up , this might lead to a spark which can ignite the fuel and cause an explosion

Planes- friction between air and plane makes it become charged , the build up of static can interfere with communications equipment

Question 18

How do you reduce the danger of static electricity? Which way to electrons flow if charge is negative ? Positive? Example of a thing that gets earthed ?

Answer 18

1)Connecting the charged object into the ground using a conductor- this is called earthing

2)earthing provides an easy route for static charged to travel into the ground , this means no charge can build up to give you a shock or spar

• if charge is negative electrons flow into the ground . If charge is positive electrons flow up the conductor from the ground
• fuel tankers get earthed to prevent sparks that might cause fuel to explode