AOS3 - how can electricity be used to transfer energy Flashcards
(32 cards)
5.2 static and current electricity
Identify the subatomic particles of an atom and their charge:
- neutron - no net charge (0)
- proton - positive net charge (+)
- electron - negative net charge (-)
5.2 static and current electricity
How can the charges of atoms change?
The charges of atoms can ONLY change by the addition OR removal of electrons and NO other subatomic particle.
5.2 static and current electricity
Define an electrical charge:
an electrical charge refers to a base property of matter (similar to mass) that causes it to experience a force (attraction or repeltion) when placed in an electric or magnetic field.
an example of this is a shock from touhing a door handle after walking on carpet (static electricity)
5.2 static and current electricity
What are the laws of electrical charges?
- like charges repel eachother (forces push away)
- opposite charges attract eachother (forces pull towards)
5.2 static and current electricity
define electrostatic force:
electrostatic force refers to the force between stationary and charged objects.
5.2 static and current electricity
What charges can objects have?
all objects contain both positive an negative charges
1. positive charges, pos > neg charges (protrons > electrons)
2. negative charges, neg > pos charges (electrons > protrons)
no neutral charge as it refers to 0 net charge (not a charge)
5.2 static and current electricity
Define the conservation of charge:
charges can ONLY be transfered, they CANNOT be created or destroyed.
meaning they also cannot be used up
5.2 static and current electricity
Give an example of the conservation of charge:
FRUCTION - rubbing a glass rod with a silk cloth
- transfers electrons from the rod to the silk
- this results in a pos charged (+) rod and a neg charged (-) silk cloth
5.2 static and current electricity
Define conductors of electricity:
conductors refer to materials where electrons (-) move freely (allows current to flow easily)
e.g. seawater, silver, gold, steal, copper, metal
5.2 static and current electricity
Define insulators of electricity:
insulators refer to materials where electrons (-) are tightly bound (substance is resistant to current flow)
e.g rubber, glass, oil, dry wood
5.2 static and current electricity
what is the key difference between a conductor and an insulator when gaining an elcetron (-)?
CONDUCTOR - when a object (conductor) gains an electron (-) the charge of the whole object becaomes negatively charged
INSULATOR - when an object (insulator) gains an electron (-), the negative charges localise in the ‘affected’ area while the other ends of the object maintain a neutral charge
C - charges contaiminate whole object
I - charges localise
5.2 static and current electricity
Define semi-conductors:
semiconductors refer to materials where electrons (-) move freely under certain conditions
e.g used in many electronic devices
5.2 static and current electricity
Define static electricity:
Static electricity refers to the electrical charge that builds up on the surface of an object when it has gained or lost electrons, and there is no continuous flow of electric current (unlike a circuit)
5.2 static and current electricity
Identify the 3 ways static electricity occurs and how it does (occur):
- FRICTION - occurs when electrons (-) are transfered from one object yp another
- CONDUCTION - occurs when electrons (-) are moved from one object to another through direct contact (for charged an neutral objects)
- INDUCTION - occurs when charges in an neutral object are re-arraged without direct contact with a charged object
5.2 static and current electricity
Give an example for all types of static electricity:
- FRICTION - rubbing hair on a balloon (balloon gains electrons)
- CONDUCTION - burning your feet on hot sand
- INDUCTION - induction cooktops/wireless charging
5.2 static and current electricity
Define current electricity:
current electricity refers to the movement of charge (electrons)
- easily controllable
- e.g. lighting, household appliences, electronic devices, transportation, power transmissions
electric charges are also called current charges and current electricity
5.2 static and current electricity
Distinguish between static electricity and current electricity:
- static electricity involves surface charge
- current electricity involves electron (-) flow
5.3 electric current and charge
define charge and it’s unit:
charge (Q) refer to the creation of movement of electrons.
units: coulomb (C)
5.3 electric current and charge
identify charge carriers:
(particles that carry electric charge through a material)
DIRECT CURENT - charge moving in one direction
ALTERNATING CURRENT - charge periodically changing direction
5.3 electric current and charge
define elementary charge:
elementary charge refers to the smallest free charge of an electron
all charges can only by whole number multiples of −1.6 × 10⁻¹⁹ (as atoms can only gain whole electrons)
5.3 electric current and charge
identify examples of electric currents:
- lightning strike
- nerve impluses
- lightbulb
- heater
5.3 electric current and charge
define current
(what are it’s 3 requirements)
current refers toa net movement of electrons in one direction
for current to flow it requires
1. only 1 complete conducting pathway (1 direction)
2. a power source (battery) to create the net movement
3. close switch (as open switch = brocken pathway)
5.3 electric current and charge
define electron current:
Electron current is the actual flow of electrons, which move from the negative terminal to the positive terminal of a power source
5.3 electric current and charge
define a conventional current:
a conventional current refers to the direction a positive charge would flow if it was free to do so. (from the positive terminal to the negative terminal of a power source)
