Download Part - Saraswathi Velu College of Engineering

515 - SARASWATHI VELU COLLEGE OF ENGINIEERING
JAMBUKULAM ROAD, MELVENKATAPURAM, SHOLINGHUR -631102 VELLORE DIST
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
QUESTION BANK –EVEN SEMESTER
SUB CODE & NAME:
147403– ELECTROMAGNETIC FIELDS
YEAR / SEM: III / IV
Unit 1 - STATIC ELECTRIC FIELDS
PART-A (Two Marks)
Part -A
1. What is a unit vector?
2. What is the cross product?
3. What is a cylindrical coordinate?
4. What is del operator?
5. What is a gradient of a scalar?
6. What is a divergence of a vector?
7. State the divergence theorem?
8. State Stoke’s theorem?
9. Define the electric field intensity?
10. State Coulomb’s law?
11. Give the expression for electric field at point P due to n number of charges?
12. What is the electric flux density?
13. What is Gauss’s law?
14. Given that D = zρ cos2 az c/m2, calculate the charge density af(1,π/4,3) and the total charge
enclosed by the cylinder of radius 1m with 2< z <2m.
15. What is electric potential and potential difference?
Unit –II
1. What is the magnetic flux density at any point due to infinitely straight conductor?
2. What is magnetic flux density at the center of torodial coil?
3. Define vector magnetic potential?
4. Define scalar magnetic potential?
5. Give Lorentz force equation?
6. What is magnetic field intensity?
7. State Biot-Savart law?
8. Define Ampere’s circuital law?
9. What is reluctance?
10. What is permeance?
11. Write down the magnetic boundary conditions?
12. What is the electric force?
13. What is magnetic moment?
14. What is the torque?
15. Express Biot-Savart law for line current, surface current, and volume current?
Unit – III
1. What is an electric dipole?
2. What is dipole moment?
3. What is the physical significance of div D?
4. What is the current density?
5. What is polarization?
6. What is dielectric strength?
7. What is dielectric material?
8. What is continuity of current equation?
9. Write the Poisson’s equation and Laplace equation?
10. State point form of Ohm’s law?
11. What is image theory?
12. Distinguish among the diamagnetic, paramagnetic, and ferromagnetic materials?
13. What is magnetic dipole moment?
14. Write the torque in closed circuit?
15. Define magnetization?
16. What is the flux linkage?
17. Define magnetic susceptibility?
18. What is inductor?
19. What is coefficient of coupling?
20. Give few similarities b/w electric circuit and magnetic circuit?
Unit –IV
1. State Faraday’s law of induction?
2. What is motional electric field?
3. Give time harmonic Maxwell’s equations in point form ?
4. Distinguish b/w field theory and circuit theory?
5. Define the displacement current?
6. State the poynthing vector?
7. What is Gauss law for magnetic filed?
8. Define the current density?
9. Distinguish b/w field theory and circuit theory?
10. Give the integral forms of Maxwell’s equations?
Unit –V
1. Mention the properties of uniform plane wave?
2. Define intrinsic impedance?
3. Define propagation constant?
4. What is lossy dielectric medium?
5. What is the attenuation constant for wave propagation in lossy dielectrics?
6. Define skin depth?
7. What are the difference b/w line, elliptical and circular polarization?
8. Find the skin depth at a frequency of 2 MHz in aluminum whereσ = 38.2 μs/m and μr = 1.
9. What is Brewster angle?
10. What is the skin effect?
11. What is slepian vector?
Part –B
Unit-I
1. State and explain Coulomb’s law and the equation of force b/w two point charges indicating
clearly the units of the quantities in the equation of force (10)
2. Derive an expression for the electric field due to a straight uniformly charged wire of length
‘L’ in meters and with a charge density of +λ c/m at the point p which lies along the
perpendicular bisector of wire. (10)
3. State and prove Gauss’s law. Describe any two applications of Gauss’s law?(16)
4. What is electric scalar potential” and derive the expression for the potential b/w two concentric
spherical shells carrying charges +Q and –Q respectively. (10)
5. Determine the variation of field from point to point due to (i) a single spherical shell of charge
with radius R1. (ii) two concentric spherical shells of charge of radii (R1) inner and R2 (outer).
(16)
6. Prove that divergence of a curl of a vector is zero, using Stoke’s theorem?(6)
7. State and prove divergence theorem?(8)
8. Obtain the expression for D and Ē using Gauss’s law?(6)
9. A circular disc of radius ‘a’ m is charge uniformly with a charge density of σ c/m2. Find the
electric field intensity at a point ‘h’ m form the disc along it’s axis.(10)
10. Given A = (y cos ax) āx + (y + ex) āz. Find  X A at the origin (8).
Unit – II
1. State and prove Ampere’s circuital law?(8)
2. A single-phase circuit comprises two parallel conductors ‘A’ and ‘ B’ in 1cm diameter and
spaced, meter apart. The conductors carry currents of +100 and –100 amps respectively.
Determine the field intensity at the surface of each conductor and also in the space exactly
midway b/w ‘A’ and ‘B’. (10)
3. Find an expression for torque acting on a square loop carrying a current a current I.(8)
4. What is a scalar magnetic potential and also derive an expression for vector magnetic potential.
(10)
5. Find an expression for magnetic field intensity at the center of a circular at wire of radius ‘a’ m
and carrying a current I in anticlockwise direction. The wire in XY plane. (10)
6. Derive an expression for the force b/w current carrying wires. Assume that the current are in
the same direction and opposite direction. (10)
7. Develop an expression for the magnetic field intensity both inside and outside a solid
cylindrical conductor of radius ‘a’ carrying a current I with uniform density and sketch the
variation of field intensity as a function of distance from the conductor axis. (10)
Unit –III
1. Explain and derive the polarization of a dielectric materials?(6)
2. Derive the conditions at a boundary b/w dielectrics in the electric field which have
permittivites ε1 and ε2.(10)
3. Derive the conditions at a boundary b/w dielectrics in the magnetic field which have
permeability μ1 and μ 2.(10)
4. A parallel plate capacitor has a plate separation ‘t’. the capacitance with air only b/w the plates
is C. When a slap of thickness ‘t’ and relative permittivity is εr is placed on one of the plates
the capacitance is ‘C’. Show that
ć/c = ε rt/(t’ + εr (t-t’)(10)
5. Explain Poisson’s and laplace equations (5)
6. Derive an expression for the capacitance of a spherical capacitor consisting of two concentric
spheres of radii and a and b. (6)
7. Derive the expression for energy stored and energy density in the magnetic field.(8)
8. Derive an expression for inductance of a solenoid with N turns and l in meter length carrying a
current of I amperes.(8)
9. Calculate the inductance of a Solenoid of 200 turns wound tightly on a cylindrical tube of 6 cm
diameter. The length of the tube is 60cm and the solenoid is in air.(8)
10. List out the properties of dielectrics material. (5)
Unit –IV
1. Summarize Maxwell’s equation for time varying fields in integral and
differential form.
2. Compare the magnitude of conduction current density and displacement
3. State and proof of Poynting Vector and pointing thorem
4. Explain the Power flow in a co-axial cable and Instantaneous Average and
Complex Poynting
Vector.
Unit –V
1. Derivation of Wave Equation
2. Derive the Uniform Plane Waves
3. Briefly explain the Wave equation in Phasor form and also Plane waves in free space and in a
homogenous material.
4. Explain the Wave equation for a conducting medium – Plane waves in lossy dielectrics –
Propagation in good conductors
5. Explain the Reflection of Plane Wave from a conductor – normal incidence – Reflection of Plane
6. Explain the Waves by a perfect dielectric – normal and oblique incidence.