# Download GTU B.Tech 2020 Summer 4th Sem 2140909 Field Theory Question Paper

Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Summer 4th Sem 2140909 Field Theory Previous Question Paper

Seat No.: ________
Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER? IV EXAMINATION ? SUMMER 2020
Subject Code: 2140909 Date:29/10/2020
Subject Name: Field Theory
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

Q.1 (a) State Gauss's law. Also write limitations of Gauss' law.
03

(b) Define and explain unit vectors in cylindrical and spherical co-ordinate
04
systems.

(c) Planes x=2 and y= -3, respectively carry charges 10 nC/m2 and 15 nC/m2.
07
If the line x=0, z=2 carries charge 10 nC/m, calculate E at (1,1,-1) due
to three charge distribution.

Q.2 (a) Define (1) Electric field intensity (2) Potential Difference (3) Potential
03

(b) State and prove Stoke's Theorem.
04

(c) Express the vector
10
=
07
+ cos + in cartesian coordinate.
Find vector B at (-3, 4, 0)) 39

OR

(c) What is an electric dipole? Derive expression for electric field intensity
07
and potential due to an electric dipole.

Q.3 (a) Derive the relation between current and current density.
03

(b) Find div D at P (5, /2, 1) if = sin + 32 cos
04

(c) State Ampere's circuit law and obtain magnetic field intensity due to
07
infinite long straight conductor carrying current I using Ampere's Circuital
law.

OR

Q.3 (a) State and Explain various types of charge distribution with mathematical
03
equation.

(b) Derive
the equation of continuity equation in integral and differential
04
form.

(c) State and prove divergence theorem.
07

Q.4 (a) Explain briefly about lossless propagation of sinusoidal voltages.
03

(b) Define dielectric strength and list three properties of dielectric material.
04

(c) Write in details about techniques of controlling EMI.
07

OR

Q.4 (a) List any three effects of EMI.
03

(b) Derive the capacitance of Co-axial cable.
04

(c) With the help of equivalent circuit derive the general wave equations for
07
the transmission line.

1

Q.5 (a) Derive the expression for the force between two differential current
03
elements.

(b) Write Maxwell's equations in point form and integral form
04

(c) State and prove Uniqueness theorem.
07

OR

Q.5 (a) Derive Poisson's and Laplace's Equations.
03
(b) State and explain Faraday's law for statically induced emf with derivation.
04
(c) Explain magnetic boundary conditions for normal component and
07
tangential component.

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2