4. CHARGES EXERT FORCES ON ONE ANOTHER LIKES
CHANGES REPEL AND UNLIKE CHARGES ATTRACT.
INSULATOR CAN BE CHARGE D BY FRICTION .
ELECTRICAL CHARGES CAN BE DETECTED BY THE
GOLD LEAF ELECTROSCOPE .
5. 7.2 ELECTRICITY
•AN ELECTRICITY CURRENT IS THE RATE OF FLOW OF
ELECTRICAL CHARGES.
•SOURCES OF ELECTRICAL ENERGY INCLUDE DRY CELL ,
MERCURY CELL , LITHIUM CELLS , NICKEL-CADMIUM
CELLS ,DYNAMOS, ELECTRICITY GENERATING STATIONS
AND SOLAR CELLS
6. •ELECTRICAL CURRENT IS A MEASURED WITH AN AMMETER .THE AMMETER MUST BE
CONNECTED IN SERIES IN THE CIRCUIT .
•THE S1 UNIT FOR CURRENT IS THE AMPERE (A)
•VOLTAGE IS THE ENERGY REQUIRED FOR ELECTRICAL CHARGES TO FLOW FROM ONE
POINT TO ANOTHER .
•VOLTAGE IS MEASURED WITH A VOLTMETER. THE VOLTMETER MUST BE
CONNECTED IN PARALLEL TO THE ELECTRICAL MUST BE CONNECTED IN PARALLEL
TO THE ELECTRICAL COMPONENT TO BE MEASURED.
•THE S1 UNIT FOR VOLTAGE IS VOLTS (V)
7. 7.5 PARALLEL AND SERIES CIRCUITS
•AN ELECTRIC CIRCUIT IS THE PATH ALONG WHICH
ELECTRICAL CHANGES FLOW .
•THE UNIT OF RESISTANCE IS THE OHM
8. •A SERIES CIRCUIT IS ONE THAT CONNECTS AN
ELECTRICAL ENERGY SOURCE WITH ITS COMPONENTS
ONE AFTER ANOTHER.
•OHM LAW STATES THE CURRENT ( I) FLOWING
THROUGH A CONDUCTOR IS DIRECTLY PROPOTIONAL
TO THE VOLTAGE (V)ACROSS THE CONDUCTOR
9. •VOLTAGE / CURRENT =RESISTANCE V/I=R
•7.6 MAGNETISM
A MAGNETIC FIELD IS THE AREA SURROUNDINGS A MAGNET
FORCES ACT.
THE PATTERN OF A MAGNETIC FIELD CAN BE FORMED BY USING
IRON FILINGS OR BY PLOTTING USING A SMALL COMPASS.
10. 7.7 ELECTROMAGNETISM
•THE FLOW OF ELECTRIC CURRENT THROUGH A STRAIGHT WIRE
PRODUCES A MAGNETIC FIELD AROUND IT. IT PRODUCES CIRCULAR
LINES OF FORCE .
•THE DIRECTION OF THE MAGNETIC FIELD THROUGH A STRAIGHT
WIRE CAN BE DETERMINED BY THE RIGHT –HAND GRIP RULE
•THE FLOWS OF ELECTRIC CURRENT THROUGH A SOLENOID HAS A
MAGNETIC FIELD LIKE THAT OF A BAR MAGNET