Physics Flashcards
Relationship between ELECTRIC FORCE and CHARGE
Electric force INCREASES as charge INCREASES
Relationship between ELECTRIC FORCE and DISTANCE
Electric force DECREASES as DISTANCE increases
Relationship between CROSS-SECTION AREA and RESISTIVITY
The bigger the CROSS-SECTION AREA, the less RESISTIVITY (exponentially)
Relationship between LENGTH and RESISTIVITY
The longer the LENGTH, the higher the RESISTIVITY (linear)
Electric Force
Newtons(N)
Charge
Coloumbs(C)
Electrical Fields
N/C
Power
Watts
Energy
J
Resistance
R
What are the three methods of charging?
conduction, induction, polarization
Charge by contact is called…?
conduction
What are two forms of conduction?
charge by friction and charge by direct contact
What happens when something is charged by friction?
begin with two neutral objects and rub them together to transfer electrons from A to B (when A has a net (+) charge and B has a net (-) charge)
What happens when something is charged by direct contact?
begin with at least one charged object, touch the charged object A to neutral object B, electrons are transferred from charged object A to neutral object B, B now has a net (-) charge
Charge without contact is called…?
Induction
What happens when something is charged by induction?
It is grounded: when an object is connected to the earth by a wire, pipe, finger, etc. so that electrons can transfer to or from the earth.
What happens when something is charged by polarization?
A separation of charges in a neutral object
The net charge created in any process is always
zero
Van de Graff generator
A Van de Graff generator is a machine that
creates and stores static charge. A rubber belt is
spun by a motor. There are metal combs that
are placed close to the belt to collect the
electrons that are rubbed off the belt as it spins.
These electrons end up on the big, hollow
sphere.
