Parts of the Atom cause Charge. 0 0 Neutron. Conductors vs. Insulators. Electrical Charge of an Atom. Sending a Charge to Ground. Charging an Object

Size: px

Start display at page:

Download "Parts of the Atom cause Charge. 0 0 Neutron. Conductors vs. Insulators. Electrical Charge of an Atom. Sending a Charge to Ground. Charging an Object"

Christiana Sullivan
7 years ago
Views:

Static Electicity Electic Chage is an electical popety o matte that ceates electic and magnetic foces The wod electic comes fom the Geek wod elekton, meaning

Static electicity means electicity that stays put Ambe Pats of the Atom cause Chage The potons and electons ae the chaged pats of an atom.

electons. Electical chages come fom the imbalance of potons and electons Moe potons than electons Positive ( ) Conductos vs.

Conducto Insulato Moe electons than potons Negative ( ) Eual potons and electons Neutal ( 0 ) 3 A conducto will unifomly distibute chages.

1 Static Electicity Electic Chage is an electical popety o matte that ceates electic and magnetic foces The wod electic comes fom the Geek wod elekton, meaning ambe. The ancient Geeks discoveed static electicity by ubbing ambe with fu. Static electicity means electicity that stays put Ambe Pats of the Atom cause Chage The potons and electons ae the chaged pats of an atom. Neuton ae neutal Potons Positive ( ) Poton Electons Negative ( ) Neutons Neutal ( 0 ) Electon 0 0 Neuton Electical Chage of an Atom Atoms can gain o lose electons. Electical chages come fom the imbalance of potons and electons Moe potons than electons Positive ( ) Conductos vs. Insulatos Conductos allow chages to flow, Insulatos do not allow chages to flow. Conducto Insulato Moe electons than potons Negative ( ) Eual potons and electons Neutal ( 0 ) 3 A conducto will unifomly distibute chages. An insulato only has ubbed aeas chaged. 4 Sending a Chage to Gound Chaging an Object Gounding can emove chages fom an object. This can pevent static spaks fom occuing. To Gound means chages ae sent to the gound o a sepaate conducto that can absob bit. This is often used fo safety when handling fuel, electonics, o dealing with lightning. 5 An object can be chaged by ubbing off electons fom one object onto anothe.

Mateials that gain a positive () electical chage (o tend to give up electons) Geatest tendency to giving up Dy human skin electons and becoming highly positive () in chage Leathe Fu is often used to

that lead would Lead collect as much static electicity as cat fu Cat fu Silk Aluminum Gives up some electons Pape Mateials that ae elatively neutal Cotton Best fo nonstatic clothes Steel Not useful

bushes used in Nickel, Coppe Wimshust electostatic geneato Bass, Silve It is supising that these metals Gold, Platinum attact electons almost as much as polyeste Polyeste Clothes have static cling

2 Mateials that gain a positive () electical chage (o tend to give up electons) Geatest tendency to giving up Dy human skin electons and becoming highly positive () in chage Leathe Fu is often used to ceate Rabbit fu static electicity The glass on you TV sceen Glass gets chaged and collects dust "Flyaway hai" is a good Human hai example of having a modeate positive () chage Nylon Wool A supise that lead would Lead collect as much static electicity as cat fu Cat fu Silk Aluminum Gives up some electons Pape Mateials that ae elatively neutal Cotton Best fo nonstatic clothes Steel Not useful fo static electicity Mateials that gain a negave ( ) electical chage (Tend to attact electons) Attacts some electons, but is Wood almost neutal Ambe Some combs ae made of had Had ubbe ubbe Coppe bushes used in Nickel, Coppe Wimshust electostatic geneato Bass, Silve It is supising that these metals Gold, Platinum attact electons almost as much as polyeste Polyeste Clothes have static cling Packing mateial seems to stick Styene (Styofoam) to eveything You can see how Saan Wap will Saan Wap stick to things Polyuethane Pull Scotch Tape off suface and Polyethylene (like Scotch Tape) it will become chaged Polypopylene Many electons will collect on Vinyl (PVC) PVC suface Silicon Geatest tendency of gatheing electons on its suface and Teflon becoming highly negave ( ) in chage Attaction of Chaged Objects Oppositely chaged objects attact Like chaged objects epel Chaged and Neutal Objects Attact Detemining Chaged Objects A chaged balloon can cause wood molecules to be polaized so it can stick to a wall. At least one is chaged Both may be chaged Both must be chaged 9 Chage by Conduction When a negative od touches a neutal dooknob, electons move fom the od to the dooknob Chage by Induction When a negative od appoaches a neutal dooknob, electons in the dooknob ae epelled causing an uneual distibution of chage. The tansfe of electons to the metal dooknob gives the dooknob a net negative chage

3 Chage by Induction Pointed objects hold a geate concentation of chage. Moe chage is contained in a tiny egion Shaing of Chage Sphees of eual size will shae chages eually Diffeent Sizes of Sphees Sphees of eual size will shae chages uneually. Chages will spead out until thee is no electic potential diffeence between them. Electic Fields Nea Conductos An Electoscope measues if thee is a chage. A solid sphee has chages evenly spead out on the suface A hollow sphee has chages entiely on the oute suface Chages will be closest togethe at shape points 3

Coulomb: Unit fo Chage The SI unit fo chage is the Coulomb

4 x 0 8 electons o potons A lightning bolt can cay 5 C to 5

elementay chage the smallest incement of chage A single

60 x 0 9 C A single poton has a chage of.

(N) K = Coulomb's Constant = 9 x 0 9 N m / C = chage

Electic Foce is Simila to Gavity Foces on Chaged Bodies

4 Coulomb: Unit fo Chage The SI unit fo chage is the Coulomb (C) Coulomb = chage of 6.4 x 0 8 electons o potons A lightning bolt can cay 5 C to 5 C of chage. elementay chage the smallest incement of chage A single electon has a chage of.60 x 0 9 C A single poton has a chage of.60 x 0 9 C Coulomb s Law Electic Foce Electic foces can push and pull objects. This is esponsible fo static cling F K A F = Foce Newtons (N) K = Coulomb's Constant = 9 x 0 9 N m / C = chage Coulombs (C) = distance between chaged paticles (m) B 9 0 Electic Foce is Simila to Gavity Foces on Chaged Bodies Electic Foce Gavity Foce F g F e k G m m Repel Attact Chaged Objects Attact Wate Electic Field Lines Could this make a Halloween mask? B a l l o o n W a t e A steam of falling wate can be moved by a chaged object This happens because wate molecules ae pola 3 4

5 Electic Field Stength E Think of gavity acceleation, g F ' K E = Electic field stength N / C F = Foce on N = positive test chage = chage ceating the field being tested The test chage ( ) must be vey small so the effect on chage being tested () is negligible!! Electic Field Lines Electic Field Lines positive chages point outwad. negative chages point inwad. The numbe of electic field lines dawn indicates the elative stength fo each chage Like chages epel Opposite chages attact Both chages ae eual in stength The positive chage is twice as stong Like chages epel Opposite chages attact 5

Electic Potential Diffeence Electical Potential Enegy and Relative Position V

field divided by the magnitude of the chage.

Volt = Joule / Coulomb d = distance the test chage is moved (m) F = Foce on

the test chage is moved pependicula to the electic field foce acting on it,

If this occus at two o moe positions it is at euipotential.

Electic Potential Diffeence in a Unifom Field An Electic Field Between

6 Electic Potential Diffeence Electical Potential Enegy and Relative Position V The wok done moving a positive test chage between two points in an electic field divided by the magnitude of the chage. VV Wok on Chage (PE) Chage Fd ' K Electic Potential Diffeence is measued in: Volt = Joule / Coulomb d = distance the test chage is moved (m) F = Foce on test chage (N) = test chage (C) Electic Potential Diffeence Euipotential When the test chage is moved pependicula to the electic field foce acting on it, no wok is pefomed. The change in electic potential enegy is zeo. If this occus at two o moe positions it is at euipotential. Move unlike chages apat V inceases Move unlike chages close V deceases Electic Potential Diffeence in a Unifom Field An Electic Field Between Paallel Plates V Ed E = Electic Field Stength (J/C) d = distance the chage is moved A unifom electic field occus between two oppositely chage flat plates. V = Ed 6

Millikan's Oil Dop Expeiment This found the chage of an electon to be.

that wee chaged due to fiction fom an atomize (spay bottle) Chaging the

When a specific chage suspended a doplet between the two plates, electical

Millikan found that the chages of dop wee all multiples of.60 x 0 9 C.

device when a battey cannot dischage fast enough.

bass notes) TV (opeate cathode ay tube) High powe lases (Insulato)

7 Millikan's Oil Dop Expeiment This found the chage of an electon to be.60 x 0 9 C Millikan s OilDop Expeiment Oil Dop Millikan spayed oil doplets that wee chaged due to fiction fom an atomize (spay bottle) Chaging the plates caused oil doplets to ise. When a specific chage suspended a doplet between the two plates, electical foce was eual to the foce of gavity. Millikan found that the chages of dop wee all multiples of.60 x 0 9 C. This meant the smallest possible uantity of chage was the chage of a single electon. Capacitos Capacitos ae used to stoe chage and can dischage in factions of a second. Symbol Capacitos can supply an instant chage to meet the powe demand of device when a battey cannot dischage fast enough. Examples include: Poweing a camea flash Music Amplifies (Especially fo bass notes) TV (opeate cathode ay tube) High powe lases (Insulato) Capacitance Capacitance is measue in Faads (F). Faad = coulomb pe Volt Faad is huge. Many capacitos ae ated in micofaads (F) which is millionth (0 6 ) of a Faad C V Electic Potential Diffeence is measued in: V = Electic Potential Diffeence = chage (Coulombs) Lage capacitos have highe capacitance because chages can be spead futhe apat 7

The Electric Potential, Electric Potential Energy and Energy Conservation. V = U/q 0. V = U/q 0 = -W/q 0 1V [Volt] =1 Nm/C

The Electric Potential, Electric Potential Energy and Energy Conservation. V = U/q 0. V = U/q 0 = -W/q 0 1V [Volt] =1 Nm/C Geneal Physics - PH Winte 6 Bjoen Seipel The Electic Potential, Electic Potential Enegy and Enegy Consevation Electic Potential Enegy U is the enegy of a chaged object in an extenal electic field (Unit