E TEST- Static electricity
2 kinds of electric charge
positive and negative
Like charges...
Repel
Unlike charges...
attract
What happens when two objects are rubbed together?
E's from one object can be transferred to the other, leaving one object with extra e's (- charged) and the other object with less e's (+ charged)
What is electric charge?
Conserved because the e's gained by one object always equal the e's lost by the other object
What is the SI unit of charge?
Coulombs
What is the charge on an electron (-e)?
-1.60e-19
What is the charge on a proton (+e)?
+1.60e-19
Are electrons quantized?
yes
Quantized
When the electrons can possess only certain discrete energy values
What is one electron or proton?
the smallest amount of charge possible
What is more charge always?
an integer multiple of the charge of one electron
Electrical conductors
materials in which charges can move freely
Electrical insulators
materials in which charges cannot move feely
Electrical semiconductors
can act as either a conductor or an insulator
How are insulators and insulated conductors charged?
by contact
What does it mean if a conductor is connected to earth?
it is grounded
What can the earth accept?
all the electrons (without becoming charged)
What does the earth supply?
electrons without becoming charged
What happens during polarization?
the molecules of a neutral object so one side is positive and one is negative
What is the surface charge of an insulator induced by?
polarizaton
When an object becomes polarized what is its net charge?
there isnt a net charge
What happens when an object is charged by contact?
the charge spreads out evenly between the two objects and both objects should end up with half the org charge
What happens when an object is charged by induction?
in induction a conductor conductor is brought near a charged object and the like charges are repelled, so they move away from the charged object
What happens if the grounding is removed before the charged object?
the conductor will be left with the opp charge
Coulombs Law equation- the force of attraction/repulsion between two charges
FE= Kc q1 q2 / r (squared)
What is Kc?
Coulombs constant = 8.99e9 Nm (squared) / C (squared)
What are q1 and q2?
the amount of charge on each object (Coulombs)
What is r?
The distance between charges (meters)
What happens if the distance doubles?
The force is reduced by 1/4 th
What happens if the charge on one particle doubles?
The force is double the whole charge