IGCSE Physics Electricity Concepts

1. Electricity
By: Timothy John
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2. Static Electricity
Static electricity refers to the build-up
of electric charge on the surface of
objects. The static charges remain on an
object until they either bleed off
to ground or are quickly neutralized by a
discharge.
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3. More Of Static
Electricity
Although charge exchange can happen
whenever any two surfaces come into
contact and separate, a static charge only
remains when at least one of the surfaces
has a high resistance to electrical flow .
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4. Electric Current
 Electric current is a The SI unit for
flow of electric measuring the rate of
charge through a
flow of electric charge
medium. This charge
is typically carried by is the ampere, which
moving electrons in is charge flowing
a conductor such through some surface
as wire. It can also be at the rate of
carried by ions in one coulomb per
an electrolyte, or by
second. Electric
both ions and
electrons in a plasma. current is measured
using an ammeter.
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5. Potential Difference
Voltage, otherwise known as electrical
potential difference or electric
tension (denoted ∆V and measured
in volts, or joules per coulomb(C ) is the
difference in electric potential between two
points — or the difference in electric
potential energy per unit charge between
two points.
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6. Deeper Into Potential
Difference
 A voltage may represent either a source of
energy, or it may represent lost or stored energy.
A voltmeter can be used to measure the voltage
between two points in a system; Voltage can be
caused by static electric fields, by electric
current through a magnetic field, by time-varying
magnetic fields, or a combination of all three.
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7. Calculation
Voltage may be calculated as:
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8. Resistance
The electrical resistance of an
electrical element is the opposition to
the passage of an electric current through
that element; the inverse quantity is
electrical conductance, the ease at
which an electric current passes. Electrical
resistance shares some conceptual
parallels with the mechanical notion
of friction. The SI unit of electrical
resistance is the ohm (Ω)
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9. More On Resistivity
For a wide variety of materials and
conditions, the electrical
resistance R is constant for a given
temperature; it does not depend on the
amount of current through or the potential
difference (voltage) across the object.
Such materials are called Ohmic
materials. For objects made of ohmic
materials the definition of the resistance,
with R being a constant for that resistor, is
known as Ohm's law. LOGO

10. How To Calculate
Resistivity?
V:Energy
I: Current
R: Resistivity
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11. Resistor Color Code
Resistors have color coded bands.
Figure 0 1 2 3 4 5 6 7 8 9
Color Black Brown Red Orange Yellow Green Blue Violet Grey White
Tolerance
5% Gold
10% Silver
20% No Band
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12. Capacitors
A capacitor is a passive two-
terminal electrical component used to
store energy in an electric field.
Capacitors are widely used in electronic
circuits for blocking direct current while
allowing alternating current to pass, in filter
networks, for smoothing the output
of power supplies, in the resonant
circuits that tune radios to
particular frequencies and for many other
purposes.
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13. Capacitors
Capacitors are widely used
in electronic circuits for
blocking direct current while
allowing alternating
current to pass, in filter
networks, for smoothing the
output of power supplies, in
the resonant circuits that
tune radios to A Polyester
particular frequencies and Capacitor, used
for CD player
for many other purposes. and e.t.c.
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14. Electric Power
In many circuits,it is important to know the
rate at which electrical energy is
transferred into other forms of energy.
Larger units of power is called as
Megawatts LOGO

15. Calculating Electric
Power
P:Power(Measured in J/s or W)
W: Watt(Measured in J)
T:Time(Measured in Seconds)
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16. Electricity In The
Home
Why Do Houses Use Parallel?
-) To receive the same current and to still
have energy running through them if one
of the lamps were not functioning properly.
The “Fuse” is used to prevent the
malfunction of electrical equipments.
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17. Dangers Of Electricity
At Home
1. Electric Shocks
> Electric shock occurs if current flows from
an electric circuit through a person’s
body.
2.Fire Risks
>If flammable material is placed too close to
a hot appliance, it may catch fire
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