P11 - Static Electricity

Question 1

direct current is the movement of charge

Answer 1

C - in one direction

Question 2

the particles that flow in the metal wire are

Answer 2

B - electrons

Question 3

explain how the plastic is charged by rubbing

Answer 3

• electrons removed by friction

- transferred to plastic

Question 4

describe the charge on the cloth

Answer 4

• opposite to charge on plastic

- but equal to charge on plastic

Question 5

this is because the dust particles …

Answer 5

C - gain electrons

Question 6

explain why the dust particles settle on the metal plates

Answer 6

• force of attraction

- plates have opposite charge to dust

Question 7

state what happens to the charge on the dust particles when they settle on the metal plate

Answer 7

• transferred to plate

Question 8

explain why charge does not build up on the metal plates

Answer 8

• metal is a conductor
• charge moves through the plate
• towards the earth (becomes earthed)

Question 9

explain how charging the door helps paint to form even coating on both sides

Answer 9

• negatively charged door attracts positively charged paint droplets
• therefore paint droplets follow lines of force and coat both sides of the door

Question 10

explain how an aircraft can become electrically charged as it flies through the air

Answer 10

• friction between the aircraft and air

- causes electron transfer between aircraft and air

Question 11

which of these diagrams shows how the charge is distributed on the metal disk

Answer 11

B

Question 12

explain why the disc has a now overall positive positive charge

Answer 12

• negative charges move from metal disc to earth

Question 13

which row shows the correct combination of the charges

Answer 13

B - negative — positive

Question 14

explain how rubbing the comb with a dry cloth gives the comb a positive electric charge

Answer 14

• friction between cloth and comb
• transfer of electrons from plastic comb to cloth
• electrons carry negative charge
• leaving excess positive charge on comb

Question 15

explain how the positively charged plastic comb picks up the small pieces of paper

Answer 15

• negative charge is induced
• on the part of paper closest to comb
• opposite charges attract

Question 16

explain how rubbing silk charges the glass

Answer 16

• charges move

- because of friction

Question 17

explain how the silk becomes charged

Answer 17

• negative electrons rubbed off glass

- giving silk negative charge

Question 18

Which diagram

Answer 18

A

Question 19

give one reason why earthing reduces risk of fire

Answer 19

• earth wire discharges aircraft to prevent sparking which could cause a fire

Question 20

the cloth has become positively charged because

Answer 20

A - negative moved from cloth to rod

Question 21

explain why the strips behave in this way after they are rubbed with a cloth

Answer 21

• they repelled

- because they had like charges

Question 22

explain why this build up could be dangerous

Answer 22

• charges are separated
• possibility of spark
• could ignite the fuel