Download 280EXTRA Credit

Extra Credit, Physics 280, Fall 014
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Please Keep in Mind:
(a) DUE DATE: NO later or sooner than the day of the first exam!
(b) There will be three other extra credit opportunities and each will
carry the same credit value..
© The overall maximum grade for un-typed solutions for the semester is
(4-points); and in case all are completely typed is (6-points). Accordingly
the grade for each set of extra credit assignment is :
0  g rade 1 if untyped ,and 0  g rade 1.5 if typed
(c) Disorganized and unreadable hand-writings , Disorganized,
unreadable , and any other possible combination of these unwanted
qualities will NOT be graded!
(d) You can get some help if needed from any source available to you.
Ultimately, you should be able to explain your presentation fully.
(e) End!
(f) (1st )(a) Calculate the electrostatic force on a uniformly charged rod of length
2 ,and charge q which lies along the axis of a uniformly charged ring of radius
R and charge q  . The centers of the charged rod and the rings are displaced by
z  z 0 .(b) Show that if z 0  ,is satisfied, then the expression of calculated
force reduces to that between point charges.
(2nd ) DUE DATE: NO later or sooner than the day of the second exam!
(2nd )(a) Calculate the electric field at an axial point
uniformly charged cylinder of charge density
2
.
z of a thin,
 , radius R, and length
z is the distance measured from the center of the cylinder. (b) What
becomes of your result in the event:
z 
?
(3) DUE DATE: NO later or sooner than the day of the third exam!
(3rd )A disk of radius R carries a total charge q uniformly distributed
over its surface. The disc rotates with a uniform angular velocity 
about the z-axis (Taken as the axis of rotation). (a) Calculate the
magnetic field at some arbitrary point on the z-axis. (b) What is the Bfield at the center of the disk?
(4) DUE DATE: NO later or sooner than the final exam time!
(4th )Two infinite, flat, parallel, and perfectly conducting metal plates lie
a
in the planes y   . The space between the plates acts as a cavity
2
oscillator in which the electric field is given by: E  E0 Cos(y / a)Sin(t )k ,
where k is a unit vector in the direction of z-axis. (a)Assuming that B is
in the x-direction, apply Ampere’s to obtain the magnetic field
everywhere inside the cavity region.(b) Use Ampere’s law to compute the
current per meter on the metal surface, and compare with the
displacement current per meter between the plates.