Stream lines
Download
1 / 20

Stream lines - PowerPoint PPT Presentation


  • 61 Views
  • Uploaded on

Stream lines . front plate slightly charged induces opposite charge on back plate. Brushes pull off charges charges collected in leyden jar (capacitor). Wimshurst Machine. Electric Field. Definition . Electric field is the

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Stream lines ' - marjean-granahan


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

front plate slightly chargedinduces opposite charge on back plate.Brushes pull off chargescharges collected in leyden jar (capacitor)

Wimshurst Machine



Definition
Definition

  • Electric field is the

    strength & direction of the forces in space surrounding a positive test charge


Electric field as coulomb s law
Electric field as coulomb’s law

  • F = q1 * (k q2 /d2)

    rewrite the force equation

    F = q1 * E

    q1 is the positive test charge

    E is the field created by charge(s) q2


Top tips on electric fieldE=0 inside a metal (faraday) cageField lines go from + to – chargesCloser field lines are stronger


A

B

-

C

+

Electric Fields

Electric Field between 2 unlike charges

Note that the distance between

electric field lines at C is shorter

than that at B.

Distance between electric field

lines at B is shorter than at A.

Electrostatics


Electric Fields

Electric Field between 2 charged plates

positive

negative

Electrostatics


+

+

+

+

+

+

+

+

-

-

-

-

-

-

-

-

Electric Fields

Electric Field between 2 charged plates

Electrostatics


Coulombs joules volts
coulombs, joules, volts

  • Coulomb= unit of charge

  • Joule = unit of energy

  • Volt= unit of energy per charge


Coulomb
coulomb

  • How many charges are in 1C? coulomb?

  • 1C is about 6 billion billion charges)(1/1.6 x 10-19 = 6.25 x 1018)

  • The man, the law

Charles Coulomb~1750


Joules of energy
Joules of energy

  • Charges have a type of energy called

    electron potential energy (PEe or U)

    High energy: + is close to +: ++

    or + is far from –: + -


It takes work to move charges against opposite an electric field
It takes work to move charges against (opposite) an electric field

High energy work needed to move + charge

(W = F*d)

E

F

+

low energy


(a) When a positive charge moves in the direction of an electric field, the field does positive work and the potential energy decreases. Work = qo E d

POSITIVE charge moving in an E field.


Volts is an energy density
Volts is an energy density electric field, the

  • Voltage is also called potential

  • 1 volt = 1 joule / 1 coulomb

  • Example: 12 V battery: every coulomb of charge has 12 joules of energy


Examples
Examples electric field, the

  • Static balloon 9 V battery (1hr,1A)

    1 joule of energy 9x104 joule energy

    0.001 C of charge 1x104C of charge

    1/.0001 = 1000 volts 9/1 = 9 Volts


Another c j v example
Another c,j,v example electric field, the

  • Van de graaf static generator has..

    1,000,00 volts (high) 1 joule of energy (low) .00001 coulombs of charge

    1,000,000 v = 1 j/ .00001c


Uniform electric field electric field, the 2 situations Point Charges

Force: F=q*E Force= k q1*q2 / d2

Electric potential energy Electric potential energy

PE= F*d = q*E*d PE = F*d = k q1*q2 / d

Voltage (electric potential)Voltage (electric potential)

V= PE/q1 = q*E*d /q = E*d V= PE/q1 = k q2 / d2

Voltage difference: Voltage difference:

DVe = D PE/q1 = E* Dd DVe = D PE/q1 = k q2 / d2 - kq2/ d1


It takes work to move charge against static forces like it takes work to lift against gravity
It takes work to move + charge against static forces like it takes work to lift against gravity

  • PEfinal

  • +++++

  • +

  • Peiniitial work = gain in PE = F*d

work


Electrostatics takes work to lift against gravitygravitational

Force: F= kq1 q2 / d2 F= Gm1m2/d2

Field E= F/q1 = kq2/d2 g = F/m1 = Gm1/d2

potential energy PE= F*d = kq1 q2 / d PE = F*d= Gm1m2/d

(using field) =qE*d = mg*h

Potential V= PE/q1 = kq2 / d U= PE/m1 = G m2 / d

(Using field) = E*d = g*h


ad