static electricity - topic 10

Question 1

electrical conductor is

Answer 1

if electrical charges can easily move through through a material, such as in metals

Question 2

electrical insulator is

Answer 2

if electrical charges cannot easily move through a material, such as plastics or rubbers

Question 3

what happens when a polythene rod is being rubbed with a cloth duster

Answer 3

electrons move from duster to rod so rod becomes negatively charged and cloth has equal positive charge. This happens because friction causes electrons to be scraped off one and onto the other

Question 4

acetate rod being rubbed with a cloth duster

Answer 4

electrons move from rod to duster. Rod becomes positively charged and cloth has an equal negative charge

Question 5

opposite charges

Answer 5

attract

Question 6

like charges

Answer 6

repel

Question 7

attraction by induction

Answer 7

electrostatic attraction occurring between charged and uncharged object

Question 8

if static negative charge is brought close to a neutral object

Answer 8

negative charges in neutral object are repelled by static charges. This creates a small positive charge on the surface of the uncharged surface which attracts the negative static charge and the two objects stick together

Question 9

if static positive charge is brought close to a neutral object

Answer 9

negative charges in object are attracted to positive charge and move towards it. This creates a negative charge on the surface of the uncharged object, which attracts the positive static charge

Question 10

rubbing balloon against your hair or clothes

Answer 10

transfers electrons to the balloon, leaving it with a negative charge. If you then hold balloon to a wall, negative charges on balloon repel negative charges on wall. This leaves a positive charge on the surface, which attracts the negatively charged balloon and they stick together

Question 11

if you run a comb through your hair

Answer 11

electrons are transferred form hair to comb, making it negatively charged. It can then be used to pick up little pieces of uncharged paper. Holding it near the paper, causes induction in the paper, causing paper pieces to jump up and stick to comb

Question 12

uses of static electricity in chimneys

Answer 12

sides of chimneys have positively charges plates, which attracts the negatively charged smoke particles. Particles stick to the plates instead of travelling out of the chimney and into astmosphere

Question 13

why electrostatic sprayers are used to spray insecticide

Answer 13

so less is blown away by the wind and the insecticide sprays evenly above the crops, giving them an even coverage. this happens as the spray gun is charged so the droplets also gain a static charge and they repel each other which causes an even spray

Question 14

how electrostatic sprayers are used to pain bikes

Answer 14

spray gun is charged, which charges the small drops of paint as they are sprayed out of the gun. The frame is given the opposite charge to the gun and so paint is attracted to bike frame

Question 15

what is a spark

Answer 15

when potential difference gets large enough, electrons can jump across the gap between the charged object and earth.

Question 16

how do you get a spark from opening a door

Answer 16

negative charge builds up on your body, due to friction between your shoes and floor as you walk. When you go to open the door that has a metal handle, electrons jump from you to metal causing a shock

Question 17

how is lightning formed

Answer 17

when raindrops and bits of ice bump together inside storm clouds, friction between them causes the top of the cloud to become positively charged and the bottom negatively charged. This creates huge PD. Electrons usually travel within the cloud or between clouds, creating lightning across the sky. However , some sparks are larger enough that the electrons can travel between cloud and ground

Question 18

dangers of static electricity

Answer 18

static electricity builds up on objects whether they are wanted or not. This can be dangerous if it leads to sparking.

Question 19

earthing

Answer 19

dangerous sparks can be prevented by connecting a charged object to the ground using a conductor such as a copper wire

Question 20

what does earthing provide the electrons

Answer 20

an easy route to travel between object and ground and this removes any excess charge that could give you a shock or a spark.

Question 21

electron flow in grounding if static charge on object is negative

Answer 21

down the conductor to the ground

Question 22

electron flow in grounding if static charge on object is positive

Answer 22

up the conducutor from the ground

Question 23

what is an electric field

Answer 23

region where an electric charge experiences a force

Question 24

where do electric field line point from positive charge

Answer 24

away

Question 25

where do electric field line point from negative charge

Answer 25

towards it

Question 26

closer together the lines in electric field ….

Answer 26

the stronger the field

Question 27

field lines radiate out from where

Answer 27

out from the centre of the point charge

Question 28

the closer to the charge you are and the closer the field lines……

Answer 28

the stronger the field

Question 29

uniform field

Answer 29

field between parallel plates and it means it has the same strength everywhere

Question 30

if field lines between charged objects point in same direction, field lines will

Answer 30

join up and objects are attracted to each other

Question 31

what do electric fields help explain

Answer 31

electrostatice events

Question 32

how electric fields help explain electrostatic events

Answer 32

when object becomes statically charged, it generates an electric field. This field interacts with the electric fields of nearby electrons in other objects. This interaction causes an attractive electrostatic force and objects move towards each other such as balloon and wall

Question 33

what is the danger of sparking when refuelling vehicles

Answer 33

static charges can build up when refuelling vehicles which can be very dangerous and sparks can cause the fuel to ignite causing a fire or explosion