Honors Physics - Electrostatics
Measuring Charge
Electrons determines charge and amount of charge.
Charge is a measure of an electron.
Unit of charge = Coulomb (C)
Charge on a single electron = -1.6 x 10^-19 C
Any charged object will be attracted to a neutral object
Force of repulsion - occurs with only like charges (1 way)
Force of attraction - occurs with opposite charge or neutral charge
When do charges attract or repel?
Which transfers: electrons or protons? Why?
Polarization of a neutral object
Electric Force
Two factors that affect the exerted force of charged objects
Distance (inverse power relationship)
Charge (direct relationship)
Electric Force can be
Charged w/ same type of charge
Charged with opposite charges
Coulomb’s Law
Equation: F= [(k)(Q1)(Q2)]/(d)^2
F = magnitude force experienced
k = Coulomb’s constant (9.00x10^9 Nm^2/C^2)
Q = charged objects
d = distance between centers of objects
The direction of force depends on the charges involved.
Newton’s law of universal gravitation
F (grav) = [(G)(m1)(m2)]/(d)^2
F = magnitude force experienced
m = masses of objects
g is used to calculator for objects near earth’s surface
Types of Objects in Electrostatics
Conductors
Materials that allow electrons to transfer across the entire exterior surface of an object
electrons travel due to chemical structure
electrons want to evenly spread out
ex: metals, water, carbon
Insulators
Materials that do not allow electrons to transfer across the surface of an object
the charge will remain at the location of charging
material of insulators prevents electrons from evenly distributing
ex: wood, dry air, glass, rubber
Semi-Conductor
ex: Si and Ge
Separation of Charge (Polarization)
process of separating opposite charges within an object
object’s charge overall stays neutral, but charges rearrange within
charges never change (electrons never transfer)
Grounding
“uncharging”
removing excess charge by process of transfer of electrons between charged object and another larger object
needs conductive pathway
Charging by Friction
Rubbing an object
as they are in close contact, it’s as if they are sharing electrons
from least electron-affinity object to most electron-affinity object
In result, two objects will have equal and opposite charges
Charging by Conduction
charge neutral object by contact of charged object
in result, both will have same type of charge (not magnitude)
Charging by Induction
charge an object without touching with charged object
polarize first, then ground, and remove inducing object
distract wanted charge, ground the removed charge, left with wanted charge
in result, two objects will have opposite charge
Honors Physics - Electrostatics
Measuring Charge
Electrons determines charge and amount of charge.
Charge is a measure of an electron.
Unit of charge = Coulomb (C)
Charge on a single electron = -1.6 x 10^-19 C
Any charged object will be attracted to a neutral object
Force of repulsion - occurs with only like charges (1 way)
Force of attraction - occurs with opposite charge or neutral charge
When do charges attract or repel?
Which transfers: electrons or protons? Why?
Polarization of a neutral object
Electric Force
Two factors that affect the exerted force of charged objects
Distance (inverse power relationship)
Charge (direct relationship)
Electric Force can be
Charged w/ same type of charge
Charged with opposite charges
Coulomb’s Law
Equation: F= [(k)(Q1)(Q2)]/(d)^2
F = magnitude force experienced
k = Coulomb’s constant (9.00x10^9 Nm^2/C^2)
Q = charged objects
d = distance between centers of objects
The direction of force depends on the charges involved.
Newton’s law of universal gravitation
F (grav) = [(G)(m1)(m2)]/(d)^2
F = magnitude force experienced
m = masses of objects
g is used to calculator for objects near earth’s surface
Types of Objects in Electrostatics
Conductors
Materials that allow electrons to transfer across the entire exterior surface of an object
electrons travel due to chemical structure
electrons want to evenly spread out
ex: metals, water, carbon
Insulators
Materials that do not allow electrons to transfer across the surface of an object
the charge will remain at the location of charging
material of insulators prevents electrons from evenly distributing
ex: wood, dry air, glass, rubber
Semi-Conductor
ex: Si and Ge
Separation of Charge (Polarization)
process of separating opposite charges within an object
object’s charge overall stays neutral, but charges rearrange within
charges never change (electrons never transfer)
Grounding
“uncharging”
removing excess charge by process of transfer of electrons between charged object and another larger object
needs conductive pathway
Charging by Friction
Rubbing an object
as they are in close contact, it’s as if they are sharing electrons
from least electron-affinity object to most electron-affinity object
In result, two objects will have equal and opposite charges
Charging by Conduction
charge neutral object by contact of charged object
in result, both will have same type of charge (not magnitude)
Charging by Induction
charge an object without touching with charged object
polarize first, then ground, and remove inducing object
distract wanted charge, ground the removed charge, left with wanted charge
in result, two objects will have opposite charge