Static electricity

Question 1

What does static mean?

Answer 1

stationary

Question 2

What is friction?

Answer 2

the force that opposes motion between two surfaces moving together

Question 3

What is an electron?

Answer 3

a small negatively charged particle orbiting the nucleus of an atom

Question 4

A charge can be . . .

Answer 4

positive or negative

Question 5

What is a static charge?

Answer 5

a charge that can’t move

Question 6

What is repulsion?

Answer 6

when two forces push against each other

Question 7

What is attraction?

Answer 7

when two forces pull each other together

Question 8

What is a conductor?

Answer 8

a material that will allow the flow of electricity through it

Question 9

What is an insulator?

Answer 9

a material that will not allow the flow of electricity through it

Question 10

How is a spark formed?

Answer 10

its formed as electrons jump from one material to another

Question 11

What is potential difference?

Answer 11

The energy transferred per unit charge

Question 12

What is an Earth wire?

Answer 12

a metal connected to an object that will safely conduct any build of static charge to the ground

Question 13

What is an electric field?

Answer 13

the region around a charge where another charge will feel a force

Question 14

What are the two rules for interaction of charges?

Answer 14

• opposite charges attract

- same charges repel

Question 15

What is static electricity?

Answer 15

a build up of static charge on the surface of an object

Question 16

How is static electricity produced?

Answer 16

when two insulators are rubbed together, friction causes electrons to be stripped from one material onto the other

Question 17

What happens when a static electricity is produced? (2 things)

Answer 17

the material that lost electrons will become positively charged

the material that gained electrons will become negatively charged

Question 18

Can metals have a static charge?

Answer 18

if they are insulated from the ground a charge can be placed on a metal
(it will spread evenly over the surface)

Question 19

What are the four uses of static electricity?

Answer 19

• paint spraying
• insecticide spraying
• photocopiers
• electrostatic smoke precipitators

Question 20

How do paint sprayers work?

Answer 20

• paint particles are given the same charge from a positively charged electron in the spray nozzle
• particles all have the same charge so repel each other
• this results in a fine mist

Question 21

Ho do photocopiers work?

Answer 21

• photo-conducting drum is positively charges until light falls on it
• light is reflected off of paper onto the drum
• areas of black don’t reflect so these areas stay charged
• black toner sticks to the charged areas (opposite charges attract)
• paper is heated so that toner sticks to the paper permanently

Question 22

How do electrostatic smoke precipitators work?

Answer 22

• smoke particles move through metal grid and are given a negative charge
• smoke particles have a different charge to the metal plates inside the chimney
• smoke particles are attracted to the metal plates, and separated from the clean waste gas

Question 23

How do insecticide sprayers work?

Answer 23

• each droplet is given the same charge
• the drops repel each other, so they spread evenly
• droplets are attracted to the Earth (opposite charges attract)
• means particles fall fast and are less likely to get blown away

Question 24

What do the field lines show about the force in an electric field?

Answer 24

field lines show the direction of the force

lines point away from a positive charge and towards a negative charge

Question 25

How does distance effect the strength of an electric field?

Answer 25

the further the distance, the weaker the electrical field

Question 26

How do field lines show the strength of the force?

Answer 26

the closer the field lines, the stronger the force

Question 27

Fill the gaps :

the field between two plates is _______ (the _____ at all points) as the lines are ________ and ______ spaced

Answer 27

the field between two plates is uniform (the same at all points) as the lines are parallel and evenly spaced

Question 28

Fill the gaps :

Interactions between fields of _________ _______ objects causes _ _____

Answer 28

interactions between fields of different charged objects causes a force

Question 29

What do field lines show?

Answer 29

Where the charged particles move along

Question 30

When is static electricity dangerous?

Fill the gaps :

_____ _____ and ________

• when the wheels rub against the ground a ______ ______ is produced
• this could result in a _____ jumping from the vehicle to the ______
• to stop this causing an explosion when fuel is transferred, an _____ ____ is connected between the ______ and the ______ to safely _______ the charge to the ground

Answer 30

petrol tankers and aeroplanes

• when the wheels rub against the ground a static charge is produced
• this could result in a spark jumping from the vehicle to the ground
• to stop this causing an explosion when fuel is transferred, an Earth line is connected between the vehicle and the ground to safely conduct the charge to the ground