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EAM601S - ELECTRICITY AND MAGNETISM - 1ST OPP - JUNE 2023 |
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n Am I BI A u n IVER s I TY
OF SCIEnCE Ano TECHnOLOGY
FACULTYOF HEALTH,NATURALRESOURCESAND APPLIEDSCIENCES
SCHOOLOF HEALTHAND APPLIEDSCIENCES
DEPARTMENTOF BIOLOGY,CHEMISTRYAND PHYSICS
QUALIFICATION: BACHELOROF SCIENCE
QUALIFICATION CODE: 07BOSC
LEVEL:6
COURSECODE: EAM601S
COURSENAME: ELECTRICITYAND MAGNETISM
SESSION:JULY2023
DURATION: 3 HOURS
PAPER:THEORY
MARKS: 100
SECONDOPPORTUNITY/SUPPLEMENTARYEXAMINATION PAPER
EXAMINER (S}
PROFMUNAWAR KARIM
MODERATOR:
DR VAINO INDONGO
INSTRUCTIONS
1. Write all your answers in the answer booklet provided.
2. Read the whole question before answering.
3. Begin each question on a new page.
PERMISSIBLEMATERIALS
Scientific Calculator
THIS PAPERCONSISTSOF 4 PAGESINCLUDINGTHIS FRONTPAGE.
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Electricity and Magnetism Final Examination June 2023
Supplemental examination
1) In the diagram below there is a collection of charges. + means +q and - means -q. What
p d<i.. E. is the flux through the surface of the sphere? Recallflux ct>E=
(20 points)
- -,.
..,.. ..,..
-r
-- ...,..
-
2) Given a uniformly charged cylinder of radius R, length land charge Q: {10 points)
a) Calculate the E-field inside the cylinder
(3 points)
b) Calculate the E-field outside the cylinder
{3 points)
c) Draw a graph of the E-field both inside and outside the cylinder
(2 points)
d) Identify points where the field is maximum and minimum. There is more than one
point where the field is minimum.
(2 points)
3) Electric potential and electric field are related by E = -dV / dr. The field is strongest
where the potential changes most rapidly. In the diagram below the metal object is
charged to a potential V. Identify the point
(10 points)
(2)
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a) Where the field is maximum.
(4 points)
b) Where the field is minimum.
(4 points)
c) Where the field has an intermediate value.
(2 points0
3) You are required to measure an unknown current/.
(20 points)
a) Set up a force balance with two anti-parallel currents each carrying a current/ and of length
l. A mass mis placed on the top current carrying conductor so that its weight balances the
repulsive force between the currents.
(10 points)
b) Draw a free-body diagram depicting equilibrium between the weight of the mass and the
force between the two currents. Using Newton's Second law write a vector equation
depicting equilibrium. At equilibrium the center-to-center distance is
r = 5mm.
(5 points)
c) From the force calculate the unknown current/ in terms of l, m and g. Let l = 0.1m, m =
1.63 x 10- 3 kg,µ 0 = 4rr x 10- 7 H/m,g = 9.80 m/s 2 .
= Use F (µ0 /4rr)/ 2 l2 /(r) 2 .
{5 points)
(3)
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4) Two charges q1 = 2nC and q2 = +0.2SnC are located on the x-axis separated by 0.3m. A third
= charge q3 -0.SnC is also placed on the x-axis.
(20 points)
a) Set up the equation for the forces acting on q3 due to q1 and q2 . (10 points)
= b) Find the locations (two solutions) on the x-axis where the force on q3 0. (10 points)
= = 5) A hollow cylindrical conductor of inner radius r 1 0.03m and outer radius r 2 0.0Sm carries a
current / = 10A along its axis.
(20 points)
a) Using Ampere's law calculate the B-field in the hollow part of the conductor.(S points)
b) The B-field outside the conductor. Show the direction of the B-field. (S points)
= c) The B-field in the solid part of the conductor. Useµ0 4rr x 10- 7 H /m. (10 points)
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