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paper 2
topic 10- electricity and circuits
energy
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Charlotte
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Cards (15)
what factors affect the energy transferred when charge flows through a component?
amount of
charge
potential
difference
across the component
define potential difference in terms of charge
the
work
done per unit
charge
when an electrical current flows through a resistor why does it heat up?
collisions between electrons and the ions in the resistors lattice
causes a transfer of kinetic energy into thermal energy
dissipated to the surroundings
give an equation relating
potential difference
to
charge
E = QV
energy transferred
= charge x P.D
give an equation linking
energy
,
current
and
potential difference
E = ITV
energy =
P.D
x current x time
how do
low resistance
wires reduce
unwanted energy transfers
?
smaller resistance will mean there are fewer collisions
therefore less energy will be wastes through heating
what are some advantages of the
heating effect
useful for
appliances
such as
toasters
or
electrical fires
where the heat is the desired product
what are some disadvantages of the
heating effect
loss of energy as heat energy can make an appliance inefficient
if an appliance
overheats
: could ruin device/
injure
the user
define power
the rate of energy transfer, or the rate of which work is done
the
energy
transferred per second is also known as...
power
what are the
units
of
power
?
watts
,
W
give an equation linking
power
and
potential difference
power =
current
x p.d
give an
equation
to work out
power
without p.d
P
=
I
2
R
I^2R
I
2
R
give an equation linking
power
and
energy
power = energy/
time
give equations
linking
power
and
resistance
P =
I
2
R
I^2R
I
2
R
, power =
current
2
^2
2
x resistance
P =
V
2
÷
R
V^2\div R
V
2
÷
R
, power =
p.d
2
^2
2
÷
\div
÷
R