Electricity and Magentism (PHYS2239)
BSc, Physics - PHYS
Semester: Resit
Level: 200
Year: 2017
Exercise 1: 17 marks
1. One point charge
is placed at (-d, 0) and another
at (+d, 0) along x-
axis of two dimensions Cartesian reference frame. Find the resulting field strength at a point of
coordinates (x, y), where d=100cm and x=y=2000mm.
2. A charge is distributed uniformly throughout a sphere of radius . Calculate the electric field:
(a) at a point outside the sphere;
(b) at a point within the sphere.
Exercise 2: 18 marks
1.
(a) What is the electric field generated by a disk of radius carrying a uniform charge density , at a
distance above the center?
(b) What is the electric potential created by this disk at a distance above the center?
2. A charge is distributed uniformly throughout a sphere of radius . Calculate the electric
potential:
(a) at a point outside the sphere;
(b) at a point within the sphere.
Exercise 3: 18 marks
1. State Biot-Savart’s law for a volume current of density
2. Justify if these following vectors in cylindrical coordinate describe -fields
and
3. a) Find the volume current density
from the vector potential: !
b) Calculate the magnetic induction field
Exercise 4: 17marks
1. Find the magnetic field a distance z above the center of a circular loop of radius , carrying a
uniform linear charge density
"
#, and spinning at constant angular velocity $%&&# '()
2. Find the vector potential it produces at the same point.
School/Faculty: Science Department: Physics Lecturer(s): Dr. O. Holtomo/ Mr. S. Pokam
Course Code: PHYS2239 Course Title: Electricity and Magnetism
Date: 03/08/2017 Hall: ASANJI Time: 11:00-14:00
Instructions: No documents. Clarity, Conclusion and Precision will be taken into account
THE UNIVERSITY OF BAMENDA
P.O BOX 39 Bambili
REPUBLIC OF CAMEROON
Peace-Work-Fatherland
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3. Determine the force on a charge *
"
# moving in the calculated magnetic field with a speed of
+
,-
"
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