ElectrostaticsElectrostatics Electrons Electrons Sitting Still Sitting Still

Charge Charge

inherent property of matter, one of the 7 fundamental unitsinherent property of matter, one of the 7 fundamental units

only two types of charge, positive & negative only two types of charge, positive & negative

charge of proton & electron are exactly equal, but charge of proton & electron are exactly equal, but oppositely chargedoppositely charged

ConstantsConstants

1 e = -1.6 x 101 e = -1.6 x 10-19-19 C C Proton is the same but + Proton is the same but +

Mass of a Proton = mMass of a Proton = mpp = 1.67 x 10 = 1.67 x 10-27-27 kg kg

Mass of an electron = mMass of an electron = mee = 9.11 x 10 = 9.11 x 10-31-31 kg kg

notice mnotice mpp = 2000 * m = 2000 * mee

Rules for looking at ChargesRules for looking at Charges

Law of Conservation of ChargeLaw of Conservation of Charge the net electric charge of a system must remain constantthe net electric charge of a system must remain constant

Like charges repel and Like charges repel and unlike charges attract.unlike charges attract.

3 ways to charge3 ways to charge1. Friction1. Friction

charge is transferred due to the charge is transferred due to the friction of materials in contact. (Since friction of materials in contact. (Since friction depends on the type of friction depends on the type of materials, so does this)materials, so does this)

2. Contact 2. Contact When 2 objects touch, e’s When 2 objects touch, e’s flow from one to the otherflow from one to the other

3. Induction 3. Induction Charging an object without Charging an object without actually touching it.actually touching it.

+-++

++-

- -

-- ++-------

+-++

++ -

- -

--++-

------

Ground

------

+++

++

++------

Ground

PolarizationPolarization

Special form of inductionSpecial form of induction

One side of an object is induced One side of an object is induced to be slightly more positive (or to be slightly more positive (or negative) than the other side.negative) than the other side.

- - - - -- - - - - --

+ + +++++ + ++++

+

+ ++++

+ ++++

4 ways to travel4 ways to travel

1.1. Insulator Insulator e’s don’t flow easily e’s don’t flow easily

2.2. Semiconductor Semiconductor sometimes conducts, sometimes conducts, sometimes insulatessometimes insulates

3.3. Conductors Conductors e’s flow easily e’s flow easily

4.4. Super conductors Super conductors substance that has substance that has no resistance when its temp gets close to no resistance when its temp gets close to absolute zero.absolute zero.