Transcript ELECTRICITY AND MAGNETISM

ELECTRICITY AND
MAGNETISM
ATOMS HAVE THREE PARTS
• PROTONS – ARE FOUND IN THE NUCLEUS
• NEUTRONS – ARE FOUND IN THE NUCLEUS
• ELECTRONS – FLY OUTSIDE THE NUCLEUS IN
THE ELECTRON CLOUD.
POSITIVE AND NEGATIVE
CHARGES
• PROTONS HAVE A POSITIVE CHARGE (+)
• ELECTRONS HAVE A NEGATIVE CHARGE (-)
NORMALLY THEY BALANCE OUT THE ATOM
BECAUSE THE NUMBER OF PROTRONS EQUALS
THE NUMBER OF ELECTRONS.
IONS
• WHEN AN ATOM BECOMES CHARGED.
IF THE ATOM LOSES A PROTON IT
BECOMES NEGATIVELY CHARGED.
IF THE ATOM LOSES AN ELECTRON IT
BECOMES POSITIVELY CHARGED.
MOVING ELECTRONS
• ELECTRONS CAN MOVE FROM ATOM
TO ATOM AND FROM OBJECT TO
OBJECT.
STATIC CHARGE
• IF YOU RUB A BALLOON ON YOUR HAIR
ELECTRONS ARE TRANSFERRED FROM
YOUR HAIR TO THE BALLOON.
• THIS CAUSES YOUR HAIR TO HAVE A
POSITIVE CHARGE.
• THIS CAUSES THE BALLOON TO HAVE A
NEGATIVE CHARGE.
• THIS CAUSES AN ATTRACTION BETWEEN
THEM.
ELECTRIC FORCE
• CHARGED OBJECTS EXERT IT ON EACH
OTHER.
• IT CAN BE ATTRACTIVE OR REPULSIVE.
ELECTRIC FIELD
• WHEN CHARGED OBJECTS EXERT A
FORCE ON EACH OTHER AT A
DISTANCE.
• THE FIELD GETS STRONGER AS YOU
GET CLOSER TO A CHARGE.
INSULATOR
• A MATERIAL IN WHICH ELECTRONS
CANNOT MOVE EASILY THROUGH.
• EXAMPLES ARE : PLASTIC, WOOD,
GLASS, AND RUBBER
CONDUCTOR
• MATERIALS IN WHICH ELECTRONS
MOVE EASILY.
• EXAMPLES ARE: METAL SUCH AS
COPPER , GOLD, AND ALUMINUM.
INDUCED CHARGE
• WHEN ELECTRONS ARE MOVED FROM ONE
OBJECT TO ANOTHER.
• EXAMPLE 1: WHEN YOU WALK ACROSS A
CARPET YOUR SHOES MAY RUB ELECTRONS
OFF THE CARPET. THE ELECTRONS SPREAD
OUT OVER YOUR SKIN.
• EXAMPLE 2: IF YOU RUB A BALLOON AGAINST
YOUR HAIR, ELECTRONS FROM YOUR HAIR
WILL MOVE TO THE BALLOON.
ELECTRIC DISCHARGE
• THE RAPID MOVEMENT OF ELECTRONS
FROM ONE OBJECT TO ANOTHER.
• EXAMPLE 1: WHEN YOU GET A SHOCK
ON YOUR HAND AFTER WALKING
ACROSS CARPET.
• EXAMPLE 2: LIGHTNING
GROUNDING
• PROVIDING A PATHWAY FOR EXCESS
CHARGES TO BE ABSORBED BY THE
EARTH.
• EXAMPLE: LIGHTNING RODS
ELECTRIC CURRENT
• THE FLOW OF ELECTRIC CHARGE.
• IT IS MEASURED IN AMPERES (AMPS).
CIRCUIT
• A CLOSED CONDUCTION LOOP WHICH
ALLOWS ELECTRIC CHARGES TO FLOW
CONTINUOUSLY.
• IT INCLUDES AT LEAST 3 PARTS:
-ELECTRIC ENERGY SOURCE (BATTERY)
-ELECTRIC CONDUCTOR (WIRE)
-SOMETHING TO USE THE ENERGY (LIGHT)
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Series circuit & diagram
VOLTAGE
• HOW MUCH ELECTRICAL POTENTIAL
ENERGY IS GAINED.
• AS VOLTAGE INCREASES MORE
POTENTIAL ENERGY IS AVAILABLE TO
BE TRANSFORMED INTO OTHER FORMS
OF ENERGY.
• IT IS MEASURED IN VOLTS (V)
BATTERIES
• CHEMICAL ENERGY CHANGES TO ELECTRIC
POTENTIAL ENERGY.
• ELECTRONS MOVE FROM THE NEGATIVE TERMINAL
TOWARDS THE POSITIVE TERMINAL.
• WHEN THE CHEMICALS IN THE BATTERY STOP
REACTING WITH EACH OTHER THE BATTERY IS
DEAD.
RESISTANCE
• THE MEASURE OF HOW DIFFICULT IT IS
FOR ELECTRONS TO FLOW THROUGH A
MATERIAL
• AS THE ELECTRONS FLOW THROUGH THE
CIRCUIT THEY COLLIDE WITH ATOMS AND
OTHER CHARGES.
• THE COLLISIONS CAUSE SOME
ELECTRICAL ENERGY TO BE CONVERTED
TO THERMAL ENERGY AND SOME TO
LIGHT ENERGY.
OHM’S LAW
VOLTAGE (IN VOLTS)=
CURRENT (IN AMPERES) X RESISTANCE (IN OHMS)
WHEN VOLTAGE IN A CIRCUIT INCREASES, THE
CURRENT INCREASES.
WHEN RESISTENCE IS INCREASED THE CURRENT
DECREASES.
SERIES CIRCUIT
• HAS ONLY ONE PATH FOR THE CIRCUIT
TO FOLLOW.
• IF THE PATH IS BROKEN THEN THE
CURRENT WILL NO LONGER FLOW.
PARALLEL CIRCUIT
• HAS MORE THAN ONE PATH FOR THE
ELECTRIC CURRENT TO FLOW.
• IF ONE PATH IS BROKEN THE CURRENT
WILL FLOW THROUGH OTHER PATHS.
FUSES AND CIRCUIT
BREAKERS
• WHEN MORE DEVICES ARE ADDED TO A
CIRCUIT, THE CURRENT INCREASES
WHICH INCREASES THE HEAT IN THE
WIRES.
• WHEN THE CURRENT BECOMES TOO
GREAT A PIECE OF METAL IN THE FUSE
MELTS.
OR
• A SWITCH ON THE BREAKER TURNS
OFF.
• THIS STOPS THE CURRENT
ELECTRIC POWER
POWER (IN WATTS) =
CURRENT (IN AMPERES) x VOLTAGE (IN
VOLTS)
QUESTIONS???
QUESTIONS???
kimberleyparkss.eq.edu.au
Series circuit & diagram