Electric charge

Question 1

What are some common electric conductors?

Answer 1

Metals such as copper and silver

Question 2

What are so common electrical insulators?

Answer 2

Plastic and rubber

Question 3

Unit for current

Answer 3

Ampere (A)

Question 4

Unit for electrical charge

Answer 4

Coulomb (C)

Question 5

Unit for energy

Answer 5

Joules (J)

Question 6

Unit for resistance

Answer 6

Ohms (Ω)

Question 7

Unit for time

Answer 7

Seconds (s)

Question 8

Unit for voltage

Answer 8

Volts (V)

Question 9

Unit of power

Answer 9

Watt (W)

Question 10

What is an insulator?

Answer 10

A material that stops current running through it

Question 11

What is a conductor?

Answer 11

A material that allows current to flow through it

Question 12

What is static charge?

Answer 12

Static charge isn’t free to move as it builds up in one place (common in insulators where current can’t flow)

Question 13

How is static charge commonly caused?

Answer 13

Usually by friction

Question 14

How does static charge occur?

Answer 14

Two insulators are rubbed together and electrons will scrape of one insulator and “jump” to another. One will have a positive electrostatic charge and the other will have a negative electrostatic charge

Question 15

Which electrostatic charge doesn’t move?

Answer 15

Positive electrostatic charges don’t move. (Only caused by electrons “jumping” away)

Question 16

Can static charges occur on conductors?

Answer 16

Yes for example cars. On the outside they can gain/lose electrons by air rushing past

Question 17

What do two opposite charges do?

Answer 17

Attract to each other

Question 18

What do the same charges do?

Answer 18

Repel from each other

Question 19

What do the electrostatic forces do as they get further appart?

Answer 19

They will weaken

Question 20

What happens when the electric charge increases on a isolated object?

Answer 20

The voltage between the object and the earth (at 0V) increases

Question 21

How is a spark caused between the earth and object?

Answer 21

If the voltage gets large enough it will cause the electrons jump across the gap (between the earth and charged object)

Question 22

Can electrostatic charges jump to earthed conductors?

Answer 22

Yes they can jump to earthed conductors nearby (this is why we get electric shocks)

Question 23

How would you investigate static electricity?

Answer 23

Using a Polythene rod you can rub it against a cloth duster, this causes the rod to become negative and the cloth to become positive

Question 24

What can happen when fuelling (fuel-filling)?

Answer 24

Static charge can build up as fuel flows out the filler pipe
This can lead to a spark (happens when there’s a big voltage difference)

Question 25

How to fix the issue of fuelling (fuel-filling)?

Answer 25

By making the nozzle out of metal the charge will be conducted away (prevents build up)
An earthing strap between the fuel tank and fuel pipe can help

Question 26

How to tell the charge of rods?

Answer 26

Suspend two rods next to each other will show their charge as they’ll repel or attract

Question 27

How does an inkjet printer work?

Answer 27

Electrically charged droplets of ink get passed between charged plates, which deflects the ink and you get a print out

Question 28

How does a photocopier work?

Answer 28

An image is projected onto and image plate, black powder attracts to the positive image plate. The paper is heated and the powder sticks

Question 29

How does lightening occur?

Answer 29

Raindrops in storm clouds knock electrons off each other causing a voltage and lightning