· PDF fileGauss law would be invalid if a) there were magnetic monopoles b) the inverse square law were not exactly correct c) Velocity of light is a constant d)

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K.S ACADEMY, SALEM- POLYTECHNIC TRB QUESTION PAPER
K.S ACADEMY, SALEM PG TRB, POLYTECHNIC TRB & TNSET COACHING CENTRE FOR PHYSICS CELL:9042976707 Page 1
PG TRB ,ENG & POLYTECHNIC TRB & TNSET
COACHING CENTRE FOR PHYSICS
UNIT 4 :ELECTROMAGNETIC THEORY
TIME: 1/2HOURS Marks: 30
*****************************************************************************
ANSWER ALL THE QUESTIONS:
1. Vector potential is a vector
a) whose curl is equal to the magnetic flux density
b) whose curl is equal to the electric field intensity
c) whose divergence is equal to the electric potential
d) which is equal to the vector product E x H
2. The effect of magnetic field acting normally on a charged particle is observed in the
following manner (ENG TRB - 2017)
a) It moves in a straight line without deviation
b) it moves in a radial path
c) it is not affected by the field
d) it moves in a direction perpendicular to the field
3. When subjected to a transverse electric field cathode rays move (POLY TRB 2012)
a) along a hyperbolic path b) down the potential gradient
c) up the potential gradient d) along a circular path
4. If E and B denotes static electric and magnetic fields, which of the following statements
is correct
a) both E and B are solenoidal b) both E and B are irrotational
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c) E is rotational and B is solenoidal d) E is irrotational and B is solenoidal
5. Gauss law would be invalid if
a) there were magnetic monopoles
b) the inverse square law were not exactly correct
c) Velocity of light is a constant
d) velocity of light is not a constant
6. Which of the following is not a correct relation? (POLY TRB 2006-2007)
a) B = A b) E = c) E = A
T d) A = B
7. The intrinsic impedance of a lossy dielectric medium is given by
a)
b)
c)
+ d)
8. If a dielectric is placed in an electric field, then field strength
A) decreases b) increases
c) remains unaltered d) becomes zero
9. Maxwell repaired Amperes law by replacing by its generalization [TNSET 2012]
a) -
b) +
c) +
d) -
10. The total instantaneous power radiated by an accelerated non relativistic charged
particle is given by
a) Lienard Wiechart formula b) Coulomb formula

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C) Larmor formula d) Langevin formula
11. The index of refraction n of a medium of permeability and permittivity is
a) = b) = c) = 00
d) =
00
12. The total energy of magnetic field is
a) . 3 b) 1
2 . 3
c) 1
2 . 3 d) 3
13. As electromagnetic waves travel in free space only one of the following can happen to
them
a) Absorption b) Attenuation c) Refraction d) Reflection
14. Poynting vector signifies
a) current density vector producing electrostatic field
b) power density vector producing electromagnetic field
c) current density vector producing electromagnetic field
d) power density vector producing electrostatic field
15. An electric charge in uniform motion produces
a) only electric field b) both electric and magnetic field
c) only magnetic field d) neither electric nor magnetic field

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16. Poynting vector gives the
a) rate of energy flow b) Intensity of electric field
c) Intensity of magnetic field d) direction of polarization
17. The intrinsic impedance of a lossy dielectric medium is given by
a)
b)
c)
+ d)
18. Poynting vector gives the
a) rate of energy flow b) Intensity of electric field
c) Intensity of magnetic field d) direction of polarization
2 MARK QUESTIONS:
19. The electric field intensity associated with a plane wave travelling in a perfect
dielectric medium is given by , = 10 cos(2 107 0.1) V/m. The velocity of
propagation of the wave and its direction are (ENG TRB - 2017)
a) 3 108
;
b) 2 108
;
c) 1 108
;
d) 1 107
;
20. The dimensional formula for 1
20
2 is identical to that of (POLY TRB 2006-2007)

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a) B2
20 b)
1
20B
2 c) 0
2
2B d)
1
2B 0
2
21. A metal sphere with 1 m radius and surface charge density of 10 Coulombs / m2 is
enclosed in a cube of 10 m side. The total outward electric displacement normal to the
surface of the cube is
a 40 Coulombs
b 10 Coulombs
c 5 Coulombs
d) None of the above
22. The electric flux passing through a hemispherical surface of radius R placed in an
electric field with the axis parallel to the field is (POLY TRB-2012)
a) 2 b) 22 c) 2 d) 23
23. The transmitting antenna of a radio station is mounted vertically. At a point 10km due
north of the transmitter the peak electric field is 1031.The magnitude of the radiated
magnetic field is
a)3.33 1010 b) 3.33 1012 c) 103 d)3 105
24. Electric charges q, q and -2q are placed at the corners of an equilateral triangle PQR of
side L. The magnitude of electric dipole moment of the system is
a) qL b) 2qL c) 4qL d) 3qL
25. Refractive index of glass is 1.5 then the wavelength of a beam of light with a frequency
o 1014 Hz in a glass (C = 3 108 )
a) 3m b)2m c)1m )10m
26. Choose the correct boundary conditions for a dielectric sphere placed in a free space
(TNSET-2012)

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a) Normal component of and tangential component of are continuous
b) Tangential component of and normal component of D are continuous
c) Tangential components of and are continuous
d) Normal component of and are continuous
27. Match List I with List II and select the correct answer using the codes given below the
lists
List I List II
P) = 0 1) . = .
Q) . = 2) . = 0
R) = 0J 3) . = 0
S) . = 0 4) . =
P Q R S
a) 2 1 4 3
b) 4 2 1 3
c) 2 4 1 3
d) 2 4 3 1
28. The potential function = 2 2 + satisfies
a Poissons equation b) Laplace equation
c Gausss law d Greens function

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29. The equation cos 2
2
+cos 2
2
+cos 2
2
= 0 is called
a Fresnels law for phase velocity b Fresnels law of wave motion
c Fresnels law of diffraction d) none of these
30. Sum of reflectivity and transmittivity is
a) Equal to unity b) > unity c) < unity d) none of these
ANSWER AT THE LAST PAGE:
&
K .S ! ( )

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· PDF fileGauss law would be invalid if a) there were magnetic monopoles b) the inverse square law were not exactly correct c) Velocity of light is a constant d)