2927746
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Mind Map by Ellie Tunnicliffe, updated more than 1 year ago
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Created by Alice Storr
almost 10 years ago
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Copied by Ellie Tunnicliffe
almost 10 years ago
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P5.
- Electricity
- Potential
Difference
- Measures the difference in energy between two
points in a circuit, measured by a Voltmeter
- same as voltage,
measured in V
- Usually measured before
and after a bulb or resistor
- same as voltage,
measured in V
- Measures the difference in energy between two
points in a circuit, measured by a Voltmeter
- Static
- Electrons move from
one object to another
and this makes the
charges change
- E.g. rubbing hair on balloon means
that negative particles/electrons
are passed to the hair. Hair
becomes negatively charged and
repel each other. Hair is attracted
to positively charged balloon.
- Electrons move from
one object to another
and this makes the
charges change
- Current
- a.c.= Alternating current
- d.c.=Direct current
- Measured in Amps
- Moving electric charges
- a.c.= Alternating current
- Resistance
- Measured
in Ohms
- resistance = Voltage (V) / Current (A)
- Resistors get hot
when current flows
through them (e.g.
lamp filament is
caused to glow)
- 2 resistors in series have more
resistance than one on its own
- Measured
in Ohms
- Power
- P (W) = current (A) x voltage (V)
- P (W) = current (A) x voltage (V)
- Potential
Difference
- Circuits
- Series
- The current will be
the same at all
points in the circuit
- p.d. across all
components
added together
= p.d. across
battery
- p.d. is biggest
across the
component
with the most
resistence
- changing the
resistance of
one component
changes p.d.
across all other
components
- The current will be
the same at all
points in the circuit
- Parallel
- current halves when the wire splits
to go down two possible routes
- Current is largest
through the
component with
smallest
resistance
- Battery pushes more current
through a component with a smaller
resistance (because it is easier)
- p.d. across all
components
added together =
p.d. across battery
- current halves when the wire splits
to go down two possible routes
- Series
- Generating
Electricity
- Electromagnetic
Induction
- When a magnet is
moved in and out
of a coil of wire
- Voltage is induced at
ends of coils of wire
- Produces d.c.
- When a magnet is
moved in and out
of a coil of wire
- Electric
Motors
- Convert
electrical
to kinetic
energy
- A coil of wire is free to rotate
between two opposite magnetic
poles. When an electric current
flows through the coil, the coil
experiences a force and moves.
- The direction of the current is
reversed every half turn using
a split ring or commutator.
- left
hand
rule
- Convert
electrical
to kinetic
energy
- Generators
- right
hand
rule
- Increasing
induced
current
- amount of turns in coil
- speed of coil rotation
- strength of magnets
- Iron core
- amount of turns in coil
- Induce a current
by spinning a
coil of wire
inside a
magnetic field,
or by spinning a
magnet inside a
coil of wire
- Makes
a.c.
- right
hand
rule
- Electromagnetic
Induction
- Transformers
- Changes the voltage
of an AC supply.
- Only works with a.c.
- Vp/Vs = Np/Ns
- Vp/Vs = voltage of
primary coil/secondary
coil Np/Ns = Number of
turns in the
primary/secondary coil
- Step-up = more turns
on the secondary coil
- Step-down = fewer turns
on the secondary coil
- Step-up = more turns
on the secondary coil
- Vp/Vs = voltage of
primary coil/secondary
coil Np/Ns = Number of
turns in the
primary/secondary coil
- Only works with a.c.
- A pair of coils wound on an iron core. The AC
in primary coil produces a changing current
and therefore changing magnetic field,
inducing a voltage in the secondary coil.
- No electrical
connection between
the primary and the
secondary coils.
- Changes the voltage
of an AC supply.
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