02 Electrostatics

Question 1

what charge do electrons have?

Answer 1

1-

Question 2

what charge do protons have

Answer 2

1+

Question 3

do neutrons have a charge?

Answer 3

no

Question 4

what does neutral charge mean in terms of electron and protons?

Answer 4

the the number of electrons and protons are equal, therefore there is no overall charge

Question 5

opposite charges…

Answer 5

attract

Question 6

like charges…

Answer 6

repel

Question 7

give 2 things that charges objects can do:

Answer 7

pick up small peices of paper
bend thins streams of water

Question 8

why is a buildup of charge dangerous?

Answer 8

because it can cause a spark

Question 9

what can sparks therefore create?

Answer 9

an explosion, if around flammable materials

Question 10

what does earthing mean?

Answer 10

when the charges current will flow form the object into the earth via a metal wire, dispelling the charge.

Question 11

Does an acetate rod become positively or negatively charged when rubbed with a cloth?

Answer 11

positively charged

Question 12

Does a polythene rod become positively or negatively charged when rubbed with a cloth?

Answer 12

negatively charged`

Question 13

how does a negatively charged balloon become attracted to a neutral wall? [4 points]

Answer 13

1. charge bllon negatively by rubbing it on a polyester sweater
2. negatively charged balloon repels electrons in wall
3. leaves a positive region on wall
4. balloon attracted to wall

Question 14

what does an equal number of = and - mean

Answer 14

neutral/no overall charge

Question 15

give 2 things charges objects can do

Answer 15

pick up small bits of paper
bend thin streams of water

Question 16

what is the name for protection against static electricity?

Answer 16

earthing

Question 17

what is earthing? [3 points]

Answer 17

metal wire attatched to object is conductor
therefore current will flow through it
so electrons will flow from object into earth

Question 18

give the three most common uses of static electricity:

Answer 18

electrostatic pain sprayer
inkjet printer
photocopier

Question 19

describe how an electrostatic paint sprayer works: [5 points]

Answer 19

1. the sray is connected to the + terminal
2. this makes all droplets charged
3. the pain droplets are repelled from the spray nozzle and from each other
4. this makes the spread out for an even coat
5. the itme being sprayed in connected to the ground/ to a negative terminal

Question 20

describe how an inkjeft printer words [5 points]

Answer 20

1. the ink from the nozzle passes through a chargine electrode, which gives the ink a negative charge
2. after passing through those, the ink passes though 2 metal deflection plates
   (if the top plate is - charged, then the ink droplets are repelled downwards)
   (making the top plate + will do the opposite and attract the ink droplets upwards.)
3. the nozzle charges the point negatively so the ink sticks to the side.

Question 21

describe how a photocopier works [5 points]

Answer 21

1. the images of the document in projected onto a + charges copying plate
2. where the light falls into the plate, the electrical charge leaks away
3. • charged black particles (toner) are attracted to the remaining + areas
4. paper is placed ober the copying plate
5. the toner is transferred to the paper (which is heated to stick better)
   &laquo_space;take photocopy off and turn to revela image&raquo_space;