FORM 2 SCIENCE BAB 7

1. Electricity
and
Magnetism
THENESSH RAJ
FORM 2

2. ENERGY
• ENERGY MEANS THE ABILITY TO DO WORK
• THE S.I.UNIT FOR ENERGY IS JOULE (J)
ELECTRICITY

3. FORM OF ENERGY
1.SOUND ENERGY
2.KINETIC ENERGY
3.ELECTRICAL ENERGY
4.GRAVITATIONAL POTENTIAL ENERGY
5.ELASTIC POTENTIAL ENERGY
6.LIGHT ENERGY
7.NUCLEAR ENERGY
8.HEAT ENERGY
9.CHEMICAL ENERGY

4. SOURCES OF
ENERGY
1.THE SUN
2.GEOTHERMAL
3.WATER
4.BIOMASS
5.FOSSIL FUEL
6.RADIOACTIVE SUBSTANCES
7.WAVE
8.WIND

5. Electrostatic Charges
•ELECTRIC CHARGES CONSIST OF POSITIVE CHARGES AND
NEGATIVE CHARGES
•THE REPULSION AMONG THESE CHARGES ARE CALLED
ELECTROSTATIC FORCES
•ELECTROSCOPE IS USED TO DETECT THE EXISTENCE OF
ELECTRIC CHARGES ON AN OBJECT

6. Electric current
ELECTRIC CURRENT CAN BE DEFINED AS THE RATE OF FLOW
OF ELECTRIC CHARGES THROUGH A CONDUCTOR

7. Current, Voltage and
Resistance
•S.I unit for electric current is ampere(A) - measured by ammeter
•The voltage is the potential difference between two points, volt(V) -
measured by voltmeter
•The unit for measuring resistance is ohm (Ω)
•The relationship between current, voltage and resistance is Ohm's
Law
V=IR

8. Flow of Electric Current in a
Series Circuit and Paralell
Circuit
ELECTRIC CIRCUIT
SERIES CIRCUIT PARALLEL CIRCUIT

9. Series Circuit
•Series circuit is made up of electrical components that are connected one
after another where the current flows through in a single path
Current,Voltage and Resistance in a Series
Circuit
•Current, I = I₁ = I₂
•Voltage, V = V₁ = V₂
•Resistance, R = R₁ = R₂

10. • Energy component in the circuit receives the
same amount of current
• Every component is controlled by the same
switch
• Increase in voltage supplies more electric
current
• When one of the electrical appliances is
damaged, other electrical appliances cease to
function
• Adding more electrical appliances increases
resistance and decreases the flow of the current
• Each electrical appliance cannot be switched
off individually
Advantages and Disadvantages of
a Series Circuit
ADVANTAGE DISADVANTAGE

11. Parallel Circuit
•Parallel circuit is separated into several different path of electrical circuit and each
parallel path has electrical components
Current,Voltage and Resistance in a PARALLEL
Circuit
•Current, I = I₁ + I₂
•Voltage, V = V₁ = V₂
•Resistance, 1/R = 1/R₁ + 1/R₂

12. • Every electrical appliance can be switched
on or off separatedly
• The increase in the number of electrical
appliances does not affect the function of
other appliances in the same circuit
•
• The voltage for every electrical appliance cannot
be adjusted because the voltage is the same as
the source of voltage
Advantages and Disadvantages of
a PARALLEL
CIRCUIT
ADVANTAGE DISADVANTAGE

13. MAGNET
Magnetism
MAGNETISM
ELECTROMAGNET

14. MAGNET
Magnet
PROPERTIES OF
MAGNET
ELECTROMAGNET
• Attracts magnetic materials
• Has poles (north pole and south
pole)
• Like poles repel, unlike poles
attracts
• Freely suspended agnet shows
north-south direction
•The area around the
magnet with magnetic
force is magnetic field
• Begin from north pole to south pole
• Closer to another where the
magnetic field is stronger
• Lines never meet or cross

15. MAGNETIC FIELD
Magnet
ELECTROMAGNET
Application of Magnets and
Electromagnets in Daily Life
• Electromagnet is a type of magnet
that has temporary magnetic effect
when electric current flows through
it
• The pattern of the magnetic field depends
on the conductor used
• The direction of the magnetic field is
determined by the direction of the electric
current
• The right hand grip rule determines the
direction of the magnetic field
• The needle of a compass uses a magnet to
show the direction of the poles
• Credit cards and debit cards have an
electromagnetic strip that stores information
• The magnetic lock on doors uses an
electromagnet to lock the doors automatically