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Electricity (Static electricity (electric charge; electrons are negatively…

- - - - negative (-) = electrons
      - positive (+) = protons
      - neutral = same number of
        positive and negative (&neutrons)
  - - - energy is passes from atom to atom through direct contact
    - - 2 objects rubbing together. When brought in contact or rubbed together, electrons may be transferred
    - - charging an object without direct contact
        
        the electrons will not jump (unless there is an immense charge,) but instead they will move towards or away from the charge within its own atoms.
        
        electron movemnt is indused ( hence the name)
        
        the object remains neutril but one side or the other will have a charge.
        
        in order for the object to fully have that charge it must be touched to the ground. the charge will then flow out into the grounds and the object will be left with a charge
  - - - insulators; materials that prevent electric charges rom flowing through them. ( e.g. plasitc, glass, rubber)
      - conductors;
        materials that allow electric charges to flow through them easily (e.g. copper, silver, gold)
      - charge distibution:
        -on conductions & insulators
        
        Insulators:
        charged particles can't move through an insulator
        
        charge isn't distributed, the charge
        stays in the same place
        
        example:
        in rubber electrons/particles don't move,
        so charge stays in the same place
        
        Conductors:
        charged particles can move through conductors
        conductors distribute charge
        
        charged particles on a conducting
        material, distribute themselves evenly
        
        however more charge gathers around
        pointy parts (>>) of a conducting material
    - - the rapid movement of excess charge from once place to another
      - e.g.
        
        lighting
        
        socks on a trampoline/carpet
        
        getting zaped on a plasic slide
        
        your hair standing up on end from rubbing a balloon
  - - - lighting hits the rod instead of the building
      - the charge is attracted to the lightning rod because:
        
        it is closer to the clouds so has a higher force of attraction
        
        the end is pointed so more charge gathers at the end, this increase the force of attraction
        
        the lightning rod is made of a good conductor
      - they are a safety devise, they help to prevent fires and stop buildings (and people) form getting electrocuted
      - they carry a charge through a wire, down/up from the earth during an electrical storm ( lighting)
        
        redirects the charge of the lightning storm.
        
        the charge is directed deep into the ground
        (buried very deep in earth, so charges are
        absorbed in a deep reserviour of charges)
- - - - components/converters
        
        resister
        
        lamp
        
        switch
        
        rheostat (variable)
        ( - all converters convert
        electrical energy into
        another form of useful energy)
      - Meters (ways of measurement)
        
        Ammeter (A), measures current
        (connected in series)
        
        Voltmeter (V), measures voltage
        (connected in parallel)
        
        Ohmetere (O), measures resistance
      - (some definitions)
        - cells, batteries, power packs
        & mains = provide electrical energy
        (they are all sources of E.E)
        
        switches = close or brake
        a circuit, enabling charge
        to flow through
        
        Fuse = (safety device), breaks
        the circuit when it gets to hot
      - sources of electrical energy/charge:
        
        single cell
        
        3 cells in series
        
        battery of cells
        
        power pack
  - - - electrical voltage = energy per coulomb
        The number of Joules of energy given
        to each coulomb (of charge)
        is called the voltage of the source
        1 volt = 1 Joule of energy per coulomb
        1 V = 1 J/C = 1 JC-1
      - potential difference (P.d) as voltage (V)
        electrical = energy (J) per coulomb
        
        voltage is the difference in electrical energy
        between 2 points,
        (when 1 coulomb of charge moves
        between those to points)
        
        Unit of P.d = volts (V)
        1V = 1000MV (millivolts)
        
        V = E/q
        V = p.d. / volatge (V)
        E = change in electrical energy (J)
        q = charge (C)
        
        Electrical energy provided = electrical energy used up
        e.g. the energy provided from the source
        = energy provided to each coloumb,
        then electrical energy converted to light energy
        & used by the lamp
        10V = 10V
      - symbol for voltage = V
        unit of measruement for voltage = Volt (V)
        measured using a voltmeter
      - electrons gain electrical energy as they flow through the source
        the energy the source supplies = the amount of energy given to each coulomb passing through it
      - voltage and energy users/converters
        
        as electrons flow around the circuit,
        they give up their energy to the converters
        (converters always take the same amount of
        energy from each coulomb flowing through it)
        
        voltage at the
        converter vs source
        
        voltage of the converters = the amount of energy a
        converter takes away/uses from each coulomb
        
        voltage of the source = the amount of energy given to each coulomb
        
        series vs parallel:
        
        voltage in series:
        
        converters are connected in series
        
        current / coulombs must give energy to the converter
        
        voltage of the converters will add up to the voltage of the source
        V tot. = V1 + V2 + V3
        
        voltage in parallel:
        
        converters are connected in parallel
        
        the coulomb in the circuit are split among branches so each electron/ coulomb goes through only 1 branch
        
        all the energy of the coulomb will be given up to that branch/converter
        
        voltage of each branch/converter = the same as the voltage of
        the source
        V tot. = V1 = V2 = V3
    - - size of current = no. of coulombs flowing per second
        1Amp. = 1 coulomb per second
        1A= 1 C/S ( Cs-1)
        1 C = 1000 MC (millicoulombs)
      - series vs parralles
        
        current is the same everywhere in a series circuit
        = because electrons flow in 1 closed loop,
        so the rate of flow is the same everywhere
        
        current devides between branches in parrallel circiuts
        = becase the flow of electrons must devide
      - I = Q/t
        I = current (A)
        Q = charge (coulumbs)
        t = time (s)
      - current = measure of Rate of flow of electrons/electric charge
        (electric charge = coulombs / measured in coulombs)
        
        energy is carried around the circuit by electrons
      - symbol for current = I
        unit of measurement of current = Amperes (amps.)
        (electric ) current is measured
        using an Ammeter
        (Ammeters must be connected in series)
      - (electrical energy is usually carried by electrons, but it can be carried by any type of charged particle, e.g. ions)
        (sometimes if current is to small the converters won't work in the circuit)
    - - Resistance = the amount a converter/branch
        resits the flow of current
        
        every converter resists the flow of electrons, flowing through it. the amount that the converter resists the flow of current (charge) is called the resistance of the converter
      - Symbol for resistance = R
        Unit of measurement for resistance = Ohm(s) n
        measured using an = Ohmmeter
        1Kn = 1000n
      - resistance in series & parallel:
        
        Series:
        total resistance increase
        total current decrease
        all converters contribute to the total circuit resistance
        (because there is only 1 branch, the current must go through and be resisted by every converter)
        R tot. = R1 + R2 + R3
        
        Parallel:
        total resistance decreases
        total current increases
        the more branches = the smaller the circuits total resistance, = therefor greater total current drawn from the source
        (because each branch draws its own current)
        branch with the greatest resistance = has the smallest current
        R tot. < resistance of the branch with the lowest resistance
      - current & voltage:
        
        Current:
        
        the current from the source = depends on the
        total amount of resistance in the circuit
        
        greater the circuit resistance...
        ... the smaller the current
        (& visa versa)
        (current is inversely proportional to resistance)
        
        Voltage:
        
        voltage of each converter = depends on the
        resistance of the particular converter
        
        greater the resistance...
        ... greater the voltage
        (voltage is proportional to resistance)
    - - I = V/R
        V = I x R
        V = voltage (V)
        I = current (A)
        R = resistance (n)
      - rules:
        current is proportional to voltage
        (if current increases/decreases, voltage does the same)
        current is inversely proportional to resistance
        voltage is proportional to resistance
  - - - power is dependent on voltage and current:
        P = V x I
        P = power (w)
        V = voltage (v)
        I = current (A)
        power = current x voltage
      - power = the electrical energy used up
        by a devise in 1 second
        E tot. = P x t
        P = power (w)
        E tot. = energy total (J)
        t= time (s)
        power = rate of use of energy /
        the rate a converter uses electrical energy
- - - - the compass ('north') arrow points towards
        the magnetic south (because opposites attract),
        witch is the geographical north
        
        the compass points away from the
        magnetic north pole (because like charges repel),
        witch is the geographical south
      - A compass is a little magnet , it s a north & south pole
        
        A compass can detect magnetic fields
- - - - by Conduction (contact)
        
        Electrons move from the charged rod
        onto the neutral electroscope.
        they go on the plate, down the stem
        and into the leaves
        
        all the parts of the electroscope are
        now the same charge, and they repel.
      - by induction (no contact):
        
        due to the presence of the negatively charged rod,
        the negative charges (electrons) in the
        neutral electroscope move
        down the stem and into the leaves,
        away from the negative rod (similer charges repel)
        
        the electroscope is still neutral but all the
        negative charge is in the leaves,
        so the leaves repel and lift
        
        the separation of the positive and negative charge
        in the same object is called induction