Static electricity (2.5) Flashcards
What happens when certain insulating materials are rubbed against each other?
they become electrically charged
(…) charged electrons are rubbed off one material and on to the other
Negatively
The material that gains electrons becomes (…) charged
negatively
The material that loses electrons is left with an (…) (…) charge
equal
positive
What happens when two electrically charged objects are brought close together?
they exert a force on each other
Two objects that carry the same type of charge (…)
repel
Two objects that carry different types of charge (…)
attract
Attraction and repulsion between two charged objects are examples of (…) force
non-contact
Rubbing surfaces produces (…)
static electricity and sparking (can hurt)
What happens when a cloth is rubbed against a polystyrene rod?
The friction causes electrons to gain energy.
Electrons gain enough energy to leave the atom and ‘rub off’ onto the polythene rod.
polystyrene rod now negatively charged, cloth now equally positively charged
What causes electrons to ‘rub off’ onto a different material?
friction
When is static electricity created?
when electrons are transferred from one material to another
What does an electrically charged object create?
an electric field around itself
How does the strength of the electrical field change in relation to the distance between the charged object and itself?
The electric field is strongest close to the charged object.
The further away from the charged object, the weaker the field.
A second charged object placed in the field experiences what?
a force
The force between two charged objects in a field gets (…) as the distance between the objects decreases/shortens
stronger
Draw the electric field pattern for an isolated positive charged sphere
Draw arrow at end of line (furthest from ball)
Draw the electric field pattern for an isolated negative charged sphere
Draw arrow at end of line (touching ball)
What is an electrical field?
The area surrounding an electric charge that may exert a force (attract or repel) on other charged particles.
How can sparking be created when objects do not touch each other?
an electric field that may exert a (non-contact) force on other charged particles, causing sparking
fields interact
unlikely to come up
How is a spark create between a positively charged person and door handle?
Static charge builds on person
a pd between person and earth is created
door at 0V, so when hand is close is enough to door, pd is large enough…
to ionise air and electrons travel between hair and hand
Learn this - 2 marker
Why does a child become electrically charged when he goes down the slide?
Friction between the child and slide
causes charge to transfer
Going down a slide causes a child’s hair to stand on end. Make a conclusion about the electrical charge on the child’s hair from this observation and explain why
all the charges (on the hair) are the same (i.e. positive or negative)
charges / hairs are repelling
Why would earthing a conveyor belt with conducting wire not have prevented plastic bottles from being charged?
Charge will not easily flow off the conveyor belt (as the conveyor belt is an insulator)
