CHAPTER 11 ELECTRICITY

ATOMIC STRUCTURE electrons - negative charge protons - positive charge neutrons – NO charge

MOST ATOMS HAVE EQUAL NUMBERS OF PROTONS AND ELECTRONS SO THEY HAVE NEUTRAL CHARGED ATOMS WITH EXTRA ELECTRONS HAVE A NEGATIVE CHARGE ATOMS MISSING ELECTRONS HAVE A POSITIVE CHARGE CHARGED ATOMS ARE CALLED IONS OBJECTS WITH LIKE CHARGES REPEL OBJECTS WITH UNLIKE CHARGES ATTRACT

CHARGE POLARIZATION ---- CENTERS OF CHARGE ARE MOVED !! EX. NEGATIVELY CHARGED BALLOON APPROACHES A NEUTRAL WALL LIKE CHARGES REPEL SO ELECTRONS FROM BALLOON PUSH ELECTRON ON WALL AWAY CREATLING A POSITIVLY CHARGED WALL.

ELECTRIC FIELD --- F = K q1 q2/d 2 D = DISTANCE K = CONSTANT q= STRENGTH OF ELECTRICAL CHARGE THE STRENGTH OF THE ELECTRIC FIELD IS PROPORTIONAL TO THE CHARGE **DOUBLE THE CHARGE THE FIELD DOUBLES ++THE STRENGTH OF THE FIELD IS INVERSELY PROPORTIONAL TO THE SQUARE OF THE DISTANCE . DOUBLE THE DISTANCE THE FIELD STENGTH GOES DOWN BY 4

COULOMBS IS A UNIT CHARGE ( C) 1 C = THE CHARGE OF 6.25 BILLION BILLION ELECTRON OR EQUAL TO THE NUMBER OF ELECTRONS THAT PASS THROUGH A 100 W LIGHT BULB EVERY SECOND

ELECTRICAL CURRENT OR ELECTRICITY – IS THE FLOW OF ELECTRONS THROUGH A CIRCUIT OBJECTS WITH LOOSE ELECTRONS ARE GOOD CONDUCTOR OF ELECTRICITY WHILE THOSE THAT HAVE TIGHTLY HELD ELECTRONS ARE POOR CONDUCTORS . OTHER PARTS OF THE ATOM ( PROTONS OR NEWTRONS ) DO NOT MOVE!!!

MEASURING ELECTRICITY AMPERE – MEASUREMENT OF THE CURRENT IN THE CIRCUIT THE NUMBER OF ELECTRONS THAT PASS EVERY SECOND 1 AMP = 1 C OF ELECTRONS / SECOND

VOLTAGE --- THE AMOUNT OF PRESSURE PUSHING THE ELECTRONS THROUGH A CIRCUIT DETERMINES THE AMOUNT OF ENERGY THE ELECTRONS HAVE AND THE AMOUNT OF WORK THEY ARE CAPABILE OF

RESISTORS – resist the flow of electron The LONGER the wire the more the resistance The THICKER the wire the more resistance CONDUCTORS HAVE LITTLE RESISTANCE INSULATOR A LOT OF RESISTANCE OHM – UNIT OF MEASURMENT FOR RESISTANCE

OHM’S LAW AMPS = VOLT/OHMS CURRENT ( AMPS ) ARE DIRECTLY PROPORATIONAL TO VOLTAGE MORE VOLTS = MORE AMPS CURRENT ( AMPS) ARE INVERSELY PROPORATIONAL TO RESISTANCE MORE RESISTANCE = LESS AMPS LESS RESISTANCE = MORE AMPS http://phet.colorado.edu/sims/ohms-law/ohms-law_en.html

ELECTRIC SHOCK – OCCURS WHEN ELECTRIC CURRENT FLOWS THROUGH YOU!!

ELECTRIC SHOCK OCCURS WHEN AN OBJECT PROVIDES A PATH TO GROUND BIRDS ON A WIRE – NO PATH PERSON ON A LADDER – PATH CAR - - NO PATH PERSON GETTING OUT OF CAR – PATH

ALTERNATING CURRENT – ELECTRONS FLOW BACK AND FORTH USED IN HOMES/ BUSINESS/SCHOOL BECAUSE IT CAN BE TRANSMITTED FROM A CENTRAL GRIND MORE EFFECIENTLY DIRECT CURRENT – ELECTRONS FLOW ONE DIRECTION USED BATTERIES . E

SERIES CIRCUITS – ELECTRICITY FLOWS ON ONE PATH SERIES CIRCUITS – ELECTRICITY FLOWS ON ONE PATH!!! CURRENT (AMPS ) IN ALL PARTS OF CIRCUIT SAME PRESSURE ( VOLTS ) USED UP BY APPLICANCES ( MOTORS /LIGHT BULB) IF ONE BULB/MOTOR BURNS OUT ENTIRE CIRCUIT STOPS WORKING

PARALLEL CIRCUIT – MORE THAN ONE PATHWAY FOR ELECTRONS TO TRAVEL . CURRENT ( AMPS ) DIVIDE EQUALLY WITH IN PARALLEL CIRCUIT PRESSURE (VOLTS) DIVIDE WITH IN PARALLEL CIRCUITS IF ONE APPLICANCE IN A PARALLEL CIRCUIT BURNS OUT THE REST WILL NOT GO OUT

CIRCUIT BREAKERS OR FUSES KEEP PARALLEL CIRCUIT FROM CARRYING TOO MUCH CURRENT SHORT CIRCUITS OCCUR WHEN BARE WIRES TOUCH AND THE APPLICANCE DOES NOT RECEIVE CURRENT. CAUSING WIRES TO MELT