Coulomb’s Law. Physics 12. Electroscope. Draw a diagram showing the forces that exist on the leaves of the electroscope when it is placed close to the Van de Graff generator. Consider the following pendulum The mass initially shares charge with an identical sphere
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.
Physics 12
Consider the following pendulum
The mass initially shares charge with an identical sphere
The two spheres then have identical charge and (in this case) the second sphere is moved toward the pendulum bob from the left, causing the pendulum to deflect
Coulomb’s Pendulum+

+
+
Physics 12
Physics 12
The test charge that is used must be small compared to the charge creating the field
If not, the test charge’s field will change the field that is being investigated
The electric field should be the same regardless of the test charge used
Test ChargeWhat are the relative magnitudes of the charges in the diagram?
What is the polarity of each of the charges?
ProblemIt is also possible to consider what happens with multiple charges:
Multiple ChargesPhysics 12
These plots show the potential due to (a) positive and (b) negative charge.
What minimum work is required by an external force to bring a charge q = 3.00 μC from a great distance away (r = infinity) to a point 0.500 m from a charge Q = 20.0 μC ?
Analogy between gravitational and electrical potential energy:
Both rocks have the same
gravitational potential, but
the bigger rock has more Ep.
Both charges have the
same electric potential,
but the 2Q charge has
more Ep.
What is the change in potential energy of the electron in going from a to b?
What is the speed of the electron as a result of this acceleration?
Repeat both calculations for a proton.
As previously seen, it is possible to produce a uniform electric field
The intensity of the field is a function of the voltage and separation of the plates
Uniform Electric FieldEquipotential Lines electric field
Equipotential Lines electric field
The Electron Volt, a Unit of Energy electric field
A Joule is too large when dealing with electrons or atoms, so electron volts are used. One electron volt (eV) is the energy gained by an electron moving through a potential difference of one volt.