Review Test 1 Sum^2er MMXI
Monday, 27-Jun-2011
Examples & HW from Textbook:
chapter 21:
Sample problem 21-1
21-6 Charge is Conserved
hw: 1, 26, 50
chapter 22:
22-9 Dipole in an Electric Field
Sample Problem 22-5
hw: 3, 39
chapter 23:
23-2 Flux Fig. 23-2
hw: 22
"Potential" Multiple Choice Questions / Concepts
The word electric is derived from the Greek word “electron” which means _________________ and when rubbed with wool it would attract other objects.
An atom that has lost or gained one or more electrons is called: _________________
Technique in which a plastic rod can give another object a charge of opposite sign without losing any of its own charge is: _________________
The algebraic sum of all the electric charges in any closed system is constant, charge can be transferred from 1 object to another , & that is the only way in which an object can acquire a net charge; is a description of: _________________
Fact that the fundamental electro-static force between point charges exhibits an inverse-square behaviour is attributed to: _________________
An electric field that is uniform in both magnitude and direction, such field lines penetrate a rectangular surface area, whose plane is oriented perpendicular to the field is a distinction of: _________________
A point charge located outside a closed surface of arbitrary shape in which lines entering the surface equal the number of lines leaving the surface, so the net electric flux through a closed surface that surrounds no charge is: _________________
An electric field can exist at any given point, even if there is no _________________ there to respond to it.
Electric charge always occurs in integral multiples of the fundamental unit of charge e is an example of: _________________
A very large conductor that can supply an unlimited amount of charge is called: _________________
Gauss’s law is a fundamental law of physics that is equivalent to: _________________ for static charges.
For highly symmetric charge distributions, _________________ can be used to calculate the electric field.
Electric potential, which is defined as the _________________, is an important derived physical concept that is related to the electric field.
The Van de Graaff generator produces large potentials in which the charge is brought to the inner surface of a larger spherical conductor by a continuous _________________.
A Van de Graaff accelerator is a device that uses the intense electric field produced by a Van de Graaff generator to accelerate ions, such as _________________.
Spherical, Cylindrical & Planar Symmetry
An equipotential surface is a 3-D surface on which the electrical potential is the same at every point.
No point can be at 2 different potentials, so equipotential surfaces for different potentials can never touch or intersect.
Electric force immensely stronger by some 39 orders of magnitude
Dipoles: a system of 2 equal & opposite charges separated by a small distance L.
Magnitude of the Electric Field is also called: "electric field strength"
Induction: technique in which a plastic rod can give another object a charge of opposite sign without losing its own charge.
Charged atom is called an ion.
Positive ion has a net positive charge, negative ion is negatively charged.
Exchange of massless photons is responsible for the electrical force, & the excahnge of massless gravitons accounts for the gravitational force.
Semi-conductors: materials that can be made to behave sometimes as insulators & as conductors
Super-conductors: materials which at low temperatures acquire zero resistance (infinite conductivity) to the flow of charge.
Electric Shielding: The difference between electric & gravitational field is: electric fields can be shielded by various materials, gravitational fields cannot be shielded.
Static charge always lies on the outside surface of any conductor.
Applications of Electrostatics
Lightning can be studied with a Van de Graaff generator, essentially consisting of a spherical dome on which charge is continuously deposited by a moving belt.
Charge can be added until the electric field at the surface of the dome becomes equal to the dielectric strength of air.
Any more charge leaks off in sparks, as shown in the above figure.
Gauss’s Law