Objective Questions and Answers

1. If Coulomb’s force on 2 C due to 5 C is 10a_x (N), the force on 5 C due to 2 C is
   1. –10a _x (N)
   2. 10a _x (N)
   3. 10a_y (N)
   4. –10a_y (N)
2. Gradient of a potential and equipotential surface are
   1. orthogonal to each other
   2. in the same direction
   3. out of phase
   4. at 45° with one another
3. The work in moving a charge between two points depends on
   1. the path
   2. Q, E and the path
   3. Q and E only
   4. Q, E and end points
4. Unit of potential is
   1. Joules
   2. N/C
   3. N/Joules
   4. Joules/C
5. Field due to infinitely long line charge along z-axis varies with
   1. ϕ
   2. z
   3. ρ
   4. both ϕ and z
6. When the surface density is in y-z plane, field varies with
   1. y
   2. z
   3. x
   4. both y and z
7. Under static conditions, ρ_υ inside an ideal conductor is
   1. 0
   2. ∞
   3. high
   4. finite
8. Under static conditions, E inside an ideal conductor is
   1. 0
   2. ∞
   3. very high
   4. finite
9. Under static conditions, H inside an ideal conductor is
   1. 0
   2. ∞
   3. very high
   4. finite
10. Boundary condition on E_tan at an ideal conductor/free space interface is
    1. 0
    2. ∞
    3. very high
    4. finite
11. In free space, for static fields,
    1. ∇ × E = 0
    2. ∇ × E = –B
    3. ∇ × E = –H
    4. ∇ × E = ∞
12. Which of the following is correct?
    1. ∇.E = ρ_v
    2. ∇.E = ρ_v / ∈₀
    3. ∇.E = −ρ_v
    4. ∇.E = ∈₀ ρ_v
13. For steady charge density
    1. ∇ . J = 0
    2. 
    3. 
    4. ∇ . J = ∈ E
14. If the number of magnetic lines of force that cut across a conductor increases, the amount of induced voltage is ________.
15. If the number of turns in a coil is high, the induced voltage is ________.
16. An induced voltage exists only when the flux is changing.

     

    (Yes/No)

17. The flux of 1 mwb increasing to 1.01 mwb in 1.0 second produces a flux change equal to
    1. 0.01 mwb/s
    2. 1.01 mwb/s
    3. 0.1 mwb/s
    4. 1μ m wb/s
18. Faraday’s law is useful to find the amount of induced voltage.

     

    (Yes/No)

19. Lines of force of two magnetic fields in the same direction assist each other to provide a stronger magnetic field.

     

    (Yes/No)

20. If the magnetic flux of 8 mwb changes to 10 mwb in 1.0 second, the rate of flux is
    1. 1.0 mwb/sec
    2. 2 mwb/sec
    3. 0 mwb/sec
    4. 18 mwb/sec
21. If the flux changes from 8 wb to 10 wb in 2 seconds, the rate of change of flux is
    1. 2 wb/sec
    2. 1 wb/sec
    3. 0 wb/sec
    4. 1 wb/sec
22. When a magnetic flux cuts across 200 turns at the rate of 2 wb/s, the induced voltage is
    1. 400 V
    2. 100 V
    3. 600 V
    4. 0 V
23. When flux changes at a constant rate, the induced voltage is
    1. constant
    2. 0
    3. ∞
    4. –∞
24. The S.I unit of magnetic flux is
    1. Weber
    2. Coulomb
    3. Tesla
    4. Gauss
25. If a magnetic flux of 4μ wb passes through an area of 5 × 10⁻⁴ m², the flux density is
    1. 8 mT
    2. 80 mT
    3. 0.8 mT
    4. 0.08 mT
26. The divergence of the curl of a magnetic field is
    1. zero
    2. ∞
    3. a vector
    4. finite
27. The curl of a gradient of scalar magnetic potential is
    1. ∞
    2. a scalar
    3. zero
    4. ampere
28. Unit of vector magnetic potential is
    1. wb/m
    2. Tesla
    3. Volts
    4. Ampere
29. Unit of scalar magnetic potential is
    1. Ampere
    2. Tesla
    3. Volts
    4. wb/m
30. Unit of permeability of a medium is
    1. Henry
    2. Henry/m
    3. Farad/m
    4. Weber
31. Unit of magnetic susceptibility is
    1. no units
    2. Henry/m
    3. wb/m
    4. Wb
32. The direction of H is the same as that of
    1. B
    2. A
    3. E
    4. Ḋ
33. Unit of ∇² is
    1. 1/m
    2. 1/m²
    3. none
    4. A-m
34. ∇ is
    1. a scalar
    2. a constant
    3. a vector
    4. integral operator
35. Ampere’s law is applicable for
    1. open path only
    2. closed path only
    3. either open or closed path
    4. square path only
36. The tangential component of a magnetic field is continuous across any discontinuity.

     

    (Yes/No)

37. The normal component of magnetic flux density is continuous.

     

    (Yes/No)

38. Force on a charge at rest due to a magnetic field is
    1. zero
    2. a constant
    3. ∞
    4. finite
39. Scalar magnetic potential in a region where J is present, is
    1. zero
    2. ∞
    3. ∇ × H
    4. finite
40. Scalar magnetic potential exists when the field is produced by a current element.

     

    (Yes/No)

41. Unit of torque is
    1. the same as that of force
    2. Newton-m²
    3. Newton-m
    4. Newton/m
42. Magnetic field lines are closed loops.

     

    (Yes/No)

43. When the current in a current element is upwards, the direction of the magnetic field is clockwise.

     

    (Yes/No)

44. If the current in a current element is downwards, the direction of the magnetic field is along a_ϕ.

     

    (Yes/No)

45. The direction of magnetisation is
    1. that of H
    2. that of A
    3. that of E
    4. that of D
46. M₁₂ = M₂₁ (Yes/No)
47. The units of self-inductance and mutual-inductance are the same. (Yes/No)
48. Energy stored in an inductor is
    1. LI²
    2. 1/2 LI²
    3. 1/2 LV²
    4. 1/2 LVI²
49. Unit of magnetic dipole moment is
    1. C-m
    2. Amp-m
    3. Amp/m
    4. Amp-m²
50. Magnetic susceptibility of free space is
    1. zero
    2. 1
    3. μ_r
    4. μ₀
51. Magnetisation satisfies the relation
    1. ∇ × M = J_b
    2. ∇ × M = J
    3. ∇ × M = 0
    4. ∇ × M = I_b
52. The self-inductance of two coils are 4 H and 9 H. If the coefficient of coupling is 0.5, the mutual-inductance between the two coils is
    1. 12 H
    2. 3 H
    3. 6 mH
    4. 10 H
53. Magnetic field in a perfect conductor is
    1. high
    2. zero
    3. moderate
    4. finite
54. The net magnetic flux emerging from any closed surface is
    1. zero
    2. constant
    3. unity
    4. finite
55. The force on a charge due to magnetic field is
    1. QVB
    2. Q V. H
    3. Q (V × B)
    4. zero
56. A conductor 1 m long carries a current of 5 mA and is at an angle of 30° with B = 1.5 wb/m². The magnitude of the force is
    1. 7.5 mN
    2. 5 mN
    3. 3.75 mN
    4. 7.5 N
57. The first Maxwell’s equation in free space is
    1. ∇ × H = D + J
    2. ∇ × H = Ḋ
    3. ∇ × H = 0
    4. ∇ × H = J
58. Identify which of the following waves do not exist in hollow waveguides:
    1. TE
    2. TM
    3. TE and TM
    4. TEM
59. Poynting vector is given by
    1. E × H
    2. E . H
    3. E × E
    4. H . E
60. Poynting vector gives
    1. rate of energy flow
    2. direction of polarisation
    3. electric field
    4. magnetic field
61. E.H of a uniform plane wave is
    1. EH
    2. 0
    3. ηE²
    4. ηH²
62. Identify the scalar quantity:
    1. V
    2. E
    3. H
    4. A
63. The minimum value of VSWR is
    1. 0
    2. 1
    3. −1
    4. 0.1
64. VSWR is
    1. V_max/ V_min
    2. V_min /V_max
    3. V_max V_min
    4. V_max +V_min
65. Poisson’s equation is
    1. ∇² V = −ρ/∈₀
    2. ∇² V = ρ/∈₀
    3. ∇² ∇ = 0
    4. ∇² V = J/∈₀
66. In conductors,
    1. ∇ × D = 0
    2. ∇ × D = ρ
    3. ∇ × D = J_s
    4. ∇ × E = J_s
67. The unit of magnetic current density is
    1. 
    2. 
    3. 
    4. 
68. If a dielectric material is placed in an electric field, the field intensity
    1. increases
    2. does not change
    3. becomes zero
    4. decreases
69. For static fields
    1. ∇ × H = D + J
    2. ∇ × H = J
    3. ∇ × H = 0
    4. ∇ × H = D
70. Two waves are said to be out of phase if their phase difference is
    1. 180°
    2. 360°
    3. 90°
    4. 270°
71. Absolute permeability of free space is
    1. 4π × 10⁻⁷ A/m
    2. 4π × 10⁻⁷ H/m
    3. 4π × 10⁻⁷ F/m
    4. 4π × 10⁻⁷ H/m²
72. For a static magnetic field
    1. ∇ × B = ρ
    2. ∇ × B = μ J
    3. ∇ . B = μ₀ J
    4. ∇ × B = 0
73. The electric field in free space is
    1. 
    2. 
    3. ∈₀ D
    4. 
74. For a uniform plane wave in the x-direction
    1. E_x = 0
    2. H_x = 0
    3. E_x = 0 and H_x = 0
    4. Ey = 0
75. A transmission line whose Z₀ = 75Ω is terminated by 75Ω. Its input impedance is
    1. 75 Ω
    2. 375 Ω
    3. 375 Ω
    4. 375 Ω
76. Displacement current density is
    1. D
    2. J
    3. ∂D/∂t
    4. ∂J/∂t
77. If Γ is the coefficient of reflection, VSWR is given by
    1. 
    2. 
    3. 
    4. 
78. Depth of penetration in free space is
    1. α
    2. 1/α
    3. 0
    4. infinity
79. When an EM wave is incident on a dielectric, it is
    1. fully transmitted
    2. fully reflected
    3. partially transmitted and partially reflected
    4. none of these
80. In circular polarisation of EM wave
    1. E_x = E_y
    2. E_x < E_y
    3. E_x > E_y
    4. E_x ≠ E_y
81. Cut-off wavelength for dominant mode in a rectangular waveguide is
    1. 1
    2. 0
    3. very high
    4. 2a
82. If the dimensions of the narrow and broad walls of a waveguide are 3 cm and 4.5 cm, cut-off wavelength for the dominant mode is
    1. 6 cm
    2. 9.0 cm
    3. 13.5 cm
    4. 1.5 cm
83. Magnetic field due to an infinitely long current element is
    1. I /4πρ
    2. I /2πρ
    3. 1² / 2πρ
    4. 1² / 4πρ
84. Tesla is the unit of
    1. magnetic flux density
    2. magnetic flux
    3. magnetisation
    4. magnetic susceptibility
85. If a line is terminated in an open circuit, the VSWR is
    1. 0
    2. 1
    3. ∞
    4. – 1
86. Complex Poynting vector, P is
    1. P = E × H*
    2. P = E × H*
    3. P = E × H*
    4. P = H × E*
87. At the line surface of a dielectric
    1. D_n1 = D_n2
    2. D_n1 − D_n2 = ρ_s
    3. D_n1 − D_n2 = J_s
    4. 
88. Brewster angle is the
    1. angle of incidence at which no reflection occurs
    2. angle of reflection
    3. angle of transmission
    4. angle of refraction
89. Distortionless condition for a transmission line is
    1. LG = RC
    2. LR = GC
    3. GR = LC
    4. LC = Q
90. Intrinsic impedance of free space is
    1. 120π Ω
    2. 300Ω
    3. 75 Ω
    4. 73Ω
91. The reflection coefficient is generally
    1. complex
    2. scalar
    3. real
    4. imaginary
92. The velocity of an EM wave in a medium whose ∈_r = 2, μ_r = 2 is
    1. 3 × 10⁸ m/s
    2. 3 × 10⁸ cm/s
    3. 1.5 × 10⁸ m/s
    4. 1.5 × 10⁸ cm/s
93. Time varying electric field is
    1. E = –∇V
    2. E = − ∇V − Ȧ
    3. E = –∇V – B
    4. E = –∇V – D
94. The polarisation of dielectric material results in the
    1. creation of electrons
    2. creation of electric dipoles
    3. creation of eddy currents
    4. creation of magnetic dipoles
95. Any electric and magnetic field, irrespective of the fields of EM waves, are
    1. perpendicular to each other
    2. parallel to each other
    3. may have any direction
    4. are in the same direction
96. Uniform plane wave is
    1. longitudinal in nature
    2. transverse in nature
    3. neither transverse nor longitudinal
    4. vertical
97. The surface impedance of a conductor is nothing but
    1. Z₀
    2. reactive impedance
    3. load impedance
    4. E_t / J _s
98. In a homogeneous medium, the direction of E is the same as
    1. D
    2. B
    3. H
    4. P
99. Magnetic susceptibility of a medium is
    1. 
    2. 
    3. 
    4. 
100. Polarisation and direction of propagation of EM wave are one and the same.

      

     (Yes/No)

101. The direction of propagation of EM wave is obtained from
     1. E × H
     2. E.H
     3. E
     4. H
102. When an EM wave undergoes reflections while propagation, its group velocity v is
     1. greater than free space velocity v₀
     2. greater than phase velocity
     3. equal to v₀
     4. less than v₀
103. A medium is isotropic if
     1. ∈ = 0
     2. ∈ = 1
     3. ∈ = scalar constant
     4. ∈ = ∞
104. A hollow rectangular waveguide acts as a
     1. high pass filter
     2. low pass filter
     3. band pass filter
     4. low frequency radiator
105. Equation of continuity is
     1. 
     2. 
     3. 
     4. ∇ × J = ρ_v
106. The electric field inside a conducting sphere is
     1. uniform
     2. zero
     3. maximum
     4. minimum
107. If VSWR is 2, magnitude of the reflection coefficient is
     1. 1/2
     2. 1/3
     3. 1
     4. –1
108. The velocity of EM wave in a conductor is
     1. very high
     2. 3 × 10⁸ m/s
     3. greater than 3 × 10⁸ m/s
     4. very low
109. The velocity of propagation in a lossless transmission line is
     1. 
     2. 
     3. 3 × 10⁸ m/s
     4. 
110. The characteristic impedance of a lossless transmission line is
     1. 
     2. 
     3. 
     4. 
111. The reflection coefficient, when a wave is incident normally on a perfect conductor, is
     1. 0
     2. 1
     3. greater than 1
     4. ∞
112. Inductance increases with the permeability of the core.

      

     (Yes/No)

113. Inductance decreases with length for the same number of turns.

      

     (Yes/No)

114. The current in an inductor changes from 10 to 16 mA in 2 seconds. The rate of change of current is
     1. 3 mA/s
     2. 6 A/s
     3. 6 A
     4. 3 A
115. The current in an inductor changes by 100 mA in 2 m sec. The rate of change of current is
     1. 50000 A/s
     2. 100 A/s
     3. 50 A/s
     4. 50 mA/s
116. The inductance of a coil which induces 20 V when the rate of change of current in 4 A/s is
     1. 5 H
     2. 10 H
     3. 80 H
     4. 16 H
117. The induced voltage across a 2 H inductance produced by a current charge of 12 A/s is
     1. 24 V
     2. 48 V
     3. 1/3 V
     4. 8 V
118. A coil L_l produces 100; wb of magnetic flux. Out of this, 50 μ wb is linked with a second coil, L₂ . Then the coefficient of coupling is
     1. 0.50
     2. 2
     3. 50
     4. 4/3
119. If two coils of L₁ = L₂ = 400 mH have coefficient of coupling of 0.2, the mutual coupling is
     1. 80 mH
     2. 40 m
     3. 800 mH
     4. 20 mH
120. In an inductance of 10 H with a current 3 A, energy stored in the inductance is
     1. 45 J
     2. 30 J
     3. 300 J
     4. 3.3 J
121. If magnitude of magnetic flux density in free space is 4π × 10⁻⁷ wb/m², the magnetic field strength is
     1. 1 A/m
     2. 4π × 10^–7 A/m
     3. 1 wb/m
     4. 4π × 10^–7 wb/m
122. The unit of m0 is
     1. H/m
     2. (b) Henry
     3. F/m
     4. H/m²
123. The unit of ∈₀ is
     1. Farad
     2. F/m
     3. F/m²
     4. H/m
124. Unit of reluctance is
     1. Henry
     2. Henry/m
     3. Weber
     4. 1/Henry
125. J in free space is
     1. 0
     2. ∞
     3. E/ σ
     4. none
126. One Neper is
     1. greater than 1 dB
     2. less than 1 dB
     3. equal to 1 dB
     4. 4.3 dB
127. For a good conductor, the depth of penetration is
     1. β
     2. α
     3. 1/β
     4. ∞
128. At low frequencies, Earth is a
     1. good conductor
     2. bad conductor
     3. excellent conductor
     4. a good capacitor
129. Unit of Poynting vector is
     1. Watts
     2. Watts/m²
     3. Volt-amp
     4. Joules
130. If reflection coefficient is complex, VSWR is
     1. scalar
     2. complex
     3. zero
     4. ∞
131. If Z_L is purely resistive and Z₀ > Z_L, VSWR is
     1. 
     2. 
     3. 0
     4. 1
132. Z₀ is defined as
     1. 
     2. 
     3. 
     4. 
133. The static electric field at the surface of a conductor is directed normal to that surface everywhere.

      

     (Yes/No)

134. The conductor surface is an equipotential surface.

      

     (Yes/No)

135. Electric field is conservative.

      

     (Yes/No)

136. Magnetic field is conservative.

      

     (Yes/No)

137. Charge density within a conductor is
     1. zero
     2. ∞
     3. moderate
     4. high
138. The surface charge density resides
     1. on the exterior surface
     2. on the interior of the surface
     3. on the middle of the conductor
     4. in the interior depth
139. In static conditions, the current flow in a conductor is
     1. zero
     2. ∞
     3. moderate
     4. low
140. The current density in silver (σ = 61.7 × 10⁶ Ω/m) when the electric field is 1.0 V/m is
     1. 61.7 × 10⁶ A/m²
     2. 6.17 × 10⁶ A/m²
     3. 617 × 10⁶ A/m²
     4. 0.617 × 10⁶ A/m²
141. The charge stored in a 40 μ F capacitor with 50 V across it is
     1. 2.0 mc
     2. 20 mc
     3. 200 mc
     4. 0.2 mc
142. The charge stored in a capacitor when a constant current of 2 μ A flows for 20 seconds is
     1. 40μ c
     2. 10μ c
     3. 400μ c
     4. 200μ c
143. The capacitance of a capacitor which is charged to 40 μ c when 20 V is applied is
     1. 2μ F
     2. 800μ F
     3. 20μ F
     4. 200μ F
144. The voltages across a capacitor of 10 μ F when a constant current of 5 mA flows for 1 sec is
     1. 50 V
     2. 500 V
     3. 5 V
     4. 0.5 V
145. If free space is replaced by a dielectric material between the plates of a capacitor, the stored energy in the capacitor
     1. decreases
     2. increases
     3. remains the same
     4. zero
146. Unit of energy density in an electrostatic field is
     1. Joule/m³
     2. Joule/m²
     3. Joules
     4. Joule/m
147. If the electric susceptibility of a medium is 3, the permeability is
     1. 4 F/m
     2. 35.416 × 10^–12 F/m
     3. 2 F/m
     4. 8 F/m
148. Energy stored in a capacitor is
     1. proportional to ∈_r
     2. inversely proportional to ∈_r
     3. independent of ∈_r
     4. proportional to 1/∈_r
149. Magnetic torque on a loop is
     1. a vector
     2. a scalar
     3. a constant
     4. zero
150. Magnetic dipole is
     1. a pair of charges
     2. a current loop
     3. a conductor
     4. an electric dipole
151. Reluctance is
     1. the reciprocal of resistance
     2. the reciprocal of inductance
     3. the reciprocal of capacitance
     4. the reciprocal of permeance
152. The unit of magnetic charge is
     1. Coulomb
     2. Ampere
     3. Ampere-metre square
     4. Ampere-metre
153. If the flux passing through a cube is equal to 10 μ c, the total charge enclosed by the cube defined by 0 ≤ x ≤ 2, 0 ≤ y ≤ 2 and 0 ≤ z ≤ 2 is
     1. 10 μ c
     2. 6 μ c
     3. 10/3 μ c
     4. 80 μ c
154. Equation ∇.(–∈ ∇V) = ρ_υ is Poisson’s equation.

      

     (Yes/No)

155. The electric susceptibility of air is
     1. 0
     2. 2
     3. 1
     4. 4
156. An electrostatic field cannot maintain a steady current in a closed circuit.

      

     (Yes/No)

157. In electrostatics, voltage and potential difference are equivalent.

      

     (Yes/No)

158. Except in electronics, voltage and potential difference are not equivalent.

      

     (Yes/No)

159. There are no isolated magnetic poles.

      

     (Yes/No)

160. There are no isolated magnetic charges.

      

     (Yes/No)

161. The lines of magnetic flux are continuous.

      

     (Yes/No)

162. The electric flux lines are continuous.

      

     (Yes/No)

163. represents
     1. magnetic current
     2. magnetic current density
     3. magnetic flux density
     4. magnetic flux
164. The electromagnetic field inside an ideal conductor is
     1. zero
     2. ∞
     3. maximum
     4. minimum
165. Time varying field can exist in a conductor (σ < ∞).

      

     (Yes/No)

166. Surface charge density, ρ_s and J_s can exist on the surface of a perfect conductor.

      

     (Yes/No)

167. At the interface between two dielectrics, J_s is
     1. zero
     2. 1
     3. ∞
     4. high
168. J_s can exist at the boundary between a conductor and a perfect dielectric.

      

     (Yes/No)

169. ρ_s can exist at the boundary between a conductor and a perfect dielectric.

      

     (Yes/No)

170. A field can exist if it satisfies
     1. Gauss’s law
     2. Faraday’s law
     3. Coulomb’s law
     4. all Maxwell’s equations
171. Source free region means
     1. σ = 0
     2. ρ_υ = 0
     3. J = 0
     4. ρ_υ = 0, σ = 0, J = 0
172. If σ = 2.0 mho/m, E = 10.0 V/m, the conduction current density is
     1. 5.0 A/m²
     2. 20.0 A/m²
     3. 40.0 A/m²
     4. 20 A
173. Maxwell’s equations give the relations between
     1. different fields
     2. different sources
     3. different boundary conditions
     4. different potentials
174. Boundary condition on J is
     1. a_n × (J₁ – J₂) = 0
     2. a_n .(J₁ – J₂) = 0
     3. J₁ =J₂
     4. (J₁ – J₂) × a_n = 0
175. Boundary condition on E is
     1. a_n × (E₁ – E₂) = 0
     2. a_n .(E₁ – E₂) = 0
     3. E₁ = E₂
     4. E_t1 – E_t2 = ρ_s
176. Boundary condition on H is
     1. a_n × (H₁ – H₂) = J_s
     2. a_n .(H₁ – H₂) = 0
     3. a_n × (H₁ – H₂) = J_s
     4. a_n .(H₁ – H₂) = 0
177. Velocity of the EM wave is
     1. inversely proportional to β
     2. inversely proportional to α
     3. directly proportional to β
     4. directly proportional to α
178. Velocity of the wave in an ideal conductor is
     1. zero
     2. very large
     3. moderate
     4. small
179. If a wave in free space has E =2 V/m, H is 1
     1. 
     2. 60π A/m
     3. 120π A/m
     4. 240π A/m
180. If wet soil has σ = 10^–2 Ω/m, ∈_r = 15, μ_r = 1, f = 60 Hz, it is a
     1. good conductor
     2. good dielectric
     3. semiconductor
     4. magnetic medium
181. If wet soil has σ = 10^–2 V/m, ∈_r = 15, μ_r = 1 at 10 GHz, it is a
     1. good conductor
     2. good dielectric
     3. semiconductor
     4. semi dielectric
182. The cosine of the angle between two vectors is
     1. sum of the products of their direction cosines
     2. difference of the products of the direction cosines of the two vectors
     3. product of the products of the direction cosines of the two vectors
     4. division of the products of the direction cosines of the two vectors
183. Equiphase surfaces are
     1. planes
     2. only lines
     3. only cones
     4. only circles
184. The wavelength of a wave travelling along the wave normal to the plane lying in y-z plane is
     1. greater than that along x-direction
     2. smaller than that along x-direction
     3. equal to that along x-direction
     4. zero
185. The phase velocity V_p of a wave travelling along the wave normal to the plane lying in y-z plane is
     1. smaller than V_p in x-direction
     2. greater than V_p in x-direction
     3. equal to V_p in x-direction
     4. infinity
186. Electric flux density and field are related by
     1. D = ∈E
     2. 
     3. D = μE
     4. D = ∈_r E
187. Magnetic flux flowing through a closed surface is nothing but the charge enclosed.

      

     (Yes/No)

188. The electric field intensity E at a point (1, 2, 2) due to (1/9) nc located at (0, 0, 0) is
     1. 33 V/m
     2. 0.333 V/m
     3. 0.33 V/m
     4. zero
189. If E is a vector, then ∇. ∇ × E is
     1. 0
     2. 1
     3. does not exist
     4. infinity
190. Maxwell’s equation, ∇×B = 0 is due to
     1. B = μ H
     2. 
     3. non-existence of a monopole
     4. B = H
191. For charge free regions,
     1. ∇. D = 0
     2. ∇.D = ρ_v
     3. ∇ .D = ρ_v / ∈
     4. ∇.D = ∈ ρ_υ
192. A static electric field cannot exist in the absence of
     1. H
     2. B
     3. Q
     4. M
193. Velocity of EM wave in free space is
     1. independent of f
     2. increases with increase in f
     3. decreases with increase in f
     4. increases with f ²
194. Divergence theorem is applicable for
     1. static fields only
     2. time varying fields only
     3. both static and time varying fields
     4. electric fields only
195. The direction of propagation of EM wave is given by
     1. the direction of E
     2. the direction of H
     3. the direction of E × H
     4. the direction of E . H
196. For uniform plane wave propagating in z-direction
     1. E_x = 0
     2. H_x = 0
     3. E_y = 0, H_y = 0
     4. E_z = 0, H_z = 0
197. For free space
     1. σ = ∞
     2. σ = 0
     3. J ≠ 0
     4. ρ_υ = ∞
198. 1 dB is
     1. 
     2. 
     3. 
     4. 
199. Velocity of propagation of EM wave is
     1. 
     2. 
     3. 
     4. 
200. The electric field for time varying potentials
     1. E = −∇V
     2. E = −∇V − Ȧ
     3. E = ∇V
     4. E = −∇V + A
201. The ratio of displacement and conduction current densities is
     1. 
     2. 
     3. 
     4. 
202. The depth penetration of a wave in a dielectric increases with increasing
     1. σ
     2. μ
     3. ∈
     4. λ
203. The cut-off frequency of dominant mode in a waveguide is
     1. lowest
     2. highest
     3. zero
     4. _∞
204. The dominant mode in a waveguide is characterised by
     1. highest cut-off wavelength
     2. lowest cut-off wavelength
     3. zero cut-off wavelength
     4. highest cut-off frequency
205. The intrinsic impedence of the medium whose σ = 0, ∈_r = 9, μ_r = 1 is
     1. 40πΩ
     2. 9Ω
     3. 120πΩ
     4. 60πΩ
206. For time varying EM fields
     1. ∇ × H = J
     2. ∇ × H = D + J
     3. ∇ × E = 0
     4. ∇ × H = 0
207. The wavelength of a wave with a propagation constant = 0.1π + j0.2π is
     1. 10 m
     2. 20 m
     3. 30 m
     4. 25 m
208. The characteristic impedance Z₀ of a lossless transmission line is
     1. 
     2. 
     3. 
     4. 
209. VSWR = 1 is obtained when
     1. Z_L = 0
     2. Z_L = ∞
     3. Z_L = Z₀
     4. Z_L is reactive
210. Relaxation time for good conductors is
     1. short
     2. long
     3. Zero
     4. ∞
211. Relaxation time for good dielectrics is
     1. short
     2. long
     3. Zero
     4. 10 ms
212. If σ = 5.8x 10⁷ mho/m, ∈_r = 1 for copper, relaxation time is
     1. 1.53 × 10^–19 sec
     2. 5.8 × 10⁻⁷
     3. 0.1724 × 10⁻⁷ sec
     4. 1.53 ms
213. For fused quartz, σ = 10 ^–17 mho/m, ∈_r = 5.0, the relaxation time is
     1. 51.2 days
     2. 5.12 days
     3. 0.512 days
     4. 0.0512 days
214. Within a conductor, ρ_v is
     1. 0
     2. ∞
     3. moderate
     4. ϕ
215. The potential difference between any two points in a conductor is
     1. zero
     2. _∞
     3. very high
     4. 10 V
216. Electrostatic screening is obtained by
     1. a conductor
     2. a dielectric
     3. a magnetic material
     4. a semiconductor
217. A wave is totally reflected when
     1. the angle of incidence (θ _i) is large
     2. θ_i is small
     3. θ_i = 0
     4. θ_i = θ_t
218. A wave is totally reflected when
     1. medium 1 is denser than medium 2
     2. medium 1 is less denser than medium 2
     3. ∈₁ = ∈₂
     4. θ_i = θ_t
219. The surface resistance of a flat conductor is equal to its
     1. DC resistance of δ thickness
     2. AC resistance of δ thickness
     3. zero
     4. _∞
220. For a lossless medium with ∈_r = 10, μ_r = 5, impedance is
     1. 266Ω
     2. 26.6Ω
     3. 2660Ω
     4. 377Ω
221. If the magnitude of H for a plane wave in free space is 2.0 m A/m, the magnitude of E is
     1. 753.4 mV/m
     2. 7.534 mV/m
     3. 75.34 mV/m
     4. 188.5 mV/m
222. If distilled water has σ = 0, ∈_r = 81 and μ_r = 0, its impedance is
     1. 418Ω
     2. 41.8Ω
     3. 9Ω
     4. 81Ω
223. A medium has μ_r = 1 and ∈_r = 25. The phase velocity of the wave in this medium is
     1. 0.6 × 10⁸ m/sec
     2. 6 × 10⁸ m/sec
     3. 0.06 × 10⁸ m/sec
     4. 0.6 × 10⁸ cm/sec
224. The magnitude of H of a plane wave in a medium is 5 A/m. The medium constants are ∈_r = 4, μ_r = 1. The average power flow is
     1. 2354 w/m²
     2. 23.54 w/m²
     3. 235.4 w/m²
     4. 2.354 w/m²
225. For a plane travelling wave if the electric energy density is 10 mJ/m³, the magnetic energy density is
     1. 10 mJ/m³
     2. 1.0 mJ/m³
     3. zero
     4. 100 mJ/m³
226. The electric field, E is due to a fixed charge is conservative because
     1. ∇ × E = 0
     2. ∇ × E = – B
     3. V.D = 0
     4. V.B = 0
227. H field is
     1. rotational
     2. irrotational
     3. transverse
     4. longitudinal
228. H field in a current-carrying region is not conservative because
     1. ∇ × H = J
     2. ∇ × H = 0
     3. ∇.H = 0
     4. ∇.D = 0
229. A magnetic circuit is a ________ followed by the flux in a magnetic material.
230. Leakage flux, produced by the coil completes its path through the medium surrounding the magnetic circuit.

      

     (Yes/No)

231. Magnetic circuits are part ________.
232. The magnetic flux density in a magnetic material is
     1. uniform
     2. non-uniform
     3. zero
     4. ∞
233. In series magnetic circuits the magnetic flux in the magnetic material is
     1. equal to the magnetic flux in air gap
     2. not equal to the magnetic flux in air gap
     3. zero
     4. ∞
234. The fringing of magnetic flux means
     1. spreading of magnetic flux in the air gap
     2. flux is zero
     3. flux is infinity
     4. flux is moderate
235. One application of electrostatic field is ________.
236. One application of magnetostatic field is ________.
237. Electric field on free charged particle
     1. increases kinetic energy of the particle
     2. decreases kinetic energy of the particle
     3. makes kinetic energy zero
     4. makes it immobile
238. Induced electric field is
     1. conservative
     2. non-conservative
     3. zero
     4. infinity
239. Poynting vector is
     1. P = E. H
     2. P = E × H
     3. P = E × H^*
     4. 
240. B is said to be linear if
     1. B and H are parallel
     2. B and H are perpendicular
     3. E and H are parallel
     4. E and H are perpendicular
241. When a plane wave travels in a dielectric medium, the average electric energy density and average magnetic density are
     1. equal
     2. zero
     3. unequal
     4. ∞
242. In a dispersive medium
     1. signal is distorted
     2. signal is not distorted
     3. E=D
     4. D=H
243. An example of a dispersive medium is
     1. conducting medium
     2. magnetic medium
     3. magnetic material
     4. non-magnetic material
244. Brewster angle is an angle of incidence at which there exists
     1. full reflection
     2. no reflection
     3. both reflection and transmission
     4. only transmission
245. If potential is anti-symmetric, the electric field is
     1. symmetric
     2. anti-symmetric
     3. not present
     4. not related to potential
246. If a line charge is along the axis of a cylinder, the flux passes through
     1. the top surface
     2. the bottom surface
     3. both the top and bottom
     4. the curved surface
247. If the line charge is along the axis of a cylinder, the Guassian surface is
     1. top surface
     2. bottom surface
     3. curved surface
     4. not present
248. If a line charge of ρ_L = 10 PC/mm is distributed along the z-axis from –∞ to ∞, the electric field on the curved surface of the cylinder whose radius is 10 cm is
     1. 1.8 V/m
     2. 18 V/m
     3. 180 V/m
     4. 1800 V/m
249. If D = 10a_x C/m², find the flux crossing 1-m² area that is normal to the axis at x = 3 m.
     1. 10 C
     2. 30 C
     3. 1.0 C
     4. 0.3 C
250. ∇.E for the field of a uniform sheet charge is
     1. zero
     2. ∞
     3. 10
     4. –∞
251. If E = 10ra_ϕ + 5a_z, ∇.E is
     1. ∞
     2. zero
     3. −∞
     4. 140 V/m²
252. If the field at a point due to a pair of charges at ±d on the z-axis is
     

     the ϕ-compnent of E is

     1. zero
     2. 
     3. 
     4. ∞
253. Two infinite sheets with a charge density ρ_s on each are located at x = ±2.0 m. The field E in −1 < x < 1 is
     1. ∞
     2. 
     3. zero
     4. 
254. If E = 10 V/m in free space, D is
     1. zero
     2. 10 ∈₀ C/m
     3. 
     4. 10 ∈₀ C/m²
255. Conduction takes place when
     1. there is a direct electrical connection
     2. there is free space
     3. the circuits are isolated
     4. the circuits are widely separated
256. Induction taken place when
     1. there is direct electrical connection
     2. there are more circuits
     3. there is magnetic coupling
     4. there is electric coupling
257. An ideal transformer has
     1. infinite permeability
     2. zero permeability
     3. μ = μ₀
     4. ∈ = ∈₀
258. An ideal transformer has
     1. winding resistance of zero
     2. winding resistance of ∞
     3. winding resistance of moderate value
     4. high capacitance value
259. An auto transformer is
     1. an ordinary transformer
     2. a step-up transformer
     3. a step-down transformer
     4. one in which two windings of a transformer are also interconnected electrically
260. An EM wave in a hollow rectangular waveguide is characterised by
     1. TEM wave
     2. only TE wave
     3. only TM wave
     4. both TE and TM waves
261. Magnetic susceptibility has units of ∈.

      

     (Yes/No)

262. Amperian is the current due to free electrons.

      

     (Yes/No)

263. is always true.

     (Yes/No)

264. Magnetisation has units of H.

      

     (Yes/No)

265. Mutual inductance, M depends on
     1. flux linkage
     2. (b) current
     3. number of turns
     4. μ and geometrical path
266. Magnetic dipole means
     1. two magnetic charges
     2. a current loop
     3. two electric charges in magnetic field
     4. electric dipole
267. Magnetic dipole moment has
     1. Weber as unit
     2. Tesla as unit
     3. Amp-m² as unit
     4. no units
268. Magnetic current density has the unit of
     1. V/m²
     2. V/m
     3. A/m
     4. A/m²
269. If an isolated semiconductor is placed in an electric field, the motion of free electrons produce an electric field that cancels the external applied field.

      

     (Yes/No)

270. A semiconductor and conductor behave in the same manner when they are subjected to electric field.

      

     (Yes/No)

271. Dielectric strength of a material indicates the maximum E field before break down.

      

     (Yes/No)

272. Polarisation results in bound charge distribution.

      

     (Yes/No)

273. The electric field just above a conductor is always
     1. normal to the surface
     2. tangential to the surface
     3. zero
     4. ∞
274. The normal component of D in a dielectric medium just above the surface of a conductor is
     1. equal to the surface charge density
     2. equal to the tangential component
     3. zero
     4. infinity
275. The normal components of D are
     1. continuous across a dielectric boundary
     2. discontinuous across a dielectric boundary
     3. zero
     4. ∞
276. The number of lines of force from a point charge of 20 C is
     1. 10
     2. 20
     3. 30
     4. 40
277. Potential difference is equal to the change in potential energy per unit charge in the limit Q → 0.

      

     (Yes/No)

278. In a charge free region, E_x = 2x, E_y = 2y and E_z is
     1. -4z
     2. 4z
     3. 2z
     4. 4
279. An electric field given by E = a_x + 2a_y + 2a_z V/m is uniform.

      

     (Yes/No)

280. The potential distribution within a conducting medium satisfies Laplace’s equation as long as the medium is homogeneous and the current distribution is time invariant.

      

     (Yes/No)

281. Relaxation time is given by
     1. 
     2. 
     3. 
     4. 
282. The relaxation time for pure water is
     1. 30 ns
     2. 40 ns
     3. 50 ns
     4. 4 s
283. The relaxation time for amber is about
     1. 40 min
     2. 70 min
     3. 70 sec
     4. 70 hrs
284. Relaxation time for copper is
     1. 1.52 × 10^-19 sec
     2. 1.52 sec
     3. 1.52 minutes
     4. 1.52 × 10^-19 minutes
285. The permeability of all non-magnetic materials is
     1. the same as that of free space
     2. zero
     3. ∞
     4. very high
286. Does a charge at rest establish a magnetic field?

      

     (Yes/No)

287. Does a charge in motion establish an electrostatic field?

      

     (Yes/No)

288. Is true?

     (Yes/No)

289. For static fields, is true.

     (Yes/No)

290. Phase velocity and the velocity of wave propagation in free space are one and the same.

      

     (Yes/No)

291. TEM does not exist in a hollow rectangular waveguide but exists in waveguides of other shapes.

      

     (Yes/No)

292. If a waveguide for s-band system has a = 7 cm, b = 3 cm and TE₁₀ propagates in z-direction, then the cut-off frequency for TE₁₀ is
     1. 2.142 GHz
     2. 21.42 GHz
     3. 0.2142 GHz
     4. 2.142 MHz
293. Cut-off frequency of TE₁₀ mode for 2.286 cm × 1.016 cm waveguide is
     1. 6.562 GHz
     2. 0.6562 GHz
     3. 65.62 GHz
     4. 6.562 MHz
294. For a square waveguide, TE₁₀ = TE₀₁.

      

     (Yes/No)

295. R, L, C and G of a transmission line are functions of frequency.

      

     (Yes/No)

296. The shunt conductance, G of a transmission line is equal to 1/R where R is the series resistance.

      

     (Yes/No)

297. R, L, C and G of a transmission line are known as secondary constants.

      

     (Yes/No)

298. The units of R, L, C and G of a transmission line are Ω, H, F, mho.

      

     (Yes/No)

299. R, L, G, C of a transmission line are called lumped constants.

      

     (Yes/No)

300. The term long line means
     1. length or more
     2. ∞
     3. 1,000 km
     4. 0.1λ length
301. Short line means its length is much less than .

     (Yes/No)

302. SWR is measured by
     1. reflectometer
     2. voltmeter
     3. ammeter
     4. power meter
303. Z₀ of a transmission line is independent of the length of the line.

      

     (Yes/No)

304. Copper loss in transmission line is more if Z₀ is small.

      

     (Yes/No)

305. Copper loss increases as the transmission line ages.

      

     (Yes/No)

306. Dielectric loss in a transmission line increases with increase in frequency.

      

     (Yes/No)

307. Radiation losses are more when the spacing between transmission lines is more.

      

     (Yes/No)

308. Radiation losses in coaxial cable are smaller than those of parallel-wire lines.

      

     (Yes/No)

309. Radiation losses become small if the frequency is increased.

      

     (Yes/No)

310. Matched load means Z_L = Z₀

      

     (Yes/No)

311. Crystallisation reduces the copper loses in transmission lines.

      

     (Yes/No)

312. Skin effect reduces the copper loses in transmission lines.

      

     (Yes/No)

313. For air, dielectric losses are very high.

      

     (Yes/No)

314. The r and x circles in Smith chart are orthogonal to each other.

      

     (Yes/No)

315. The perimeter of the outer rim of the Smith chart is of length.

     (Yes/No)

316. VSWR is given by .

     (Yes/No)

317. If R_L > Z₀, VSWR is given by R_L/Z₀.

      

     (Yes/No)

318. If Z_L = 100+j200 and Z₀ = 50Ω, the normalised impedance is
     1. 1 + j2
     2. 2 + j4
     3. 
     4. 6
319. VSWR has a range of 1 ≤ VSWR < ∞.

      

     (Yes/No)

320. VSWR has a range of 0 ≤ VSWR ≤ ∞.

      

     (Yes/No)

321. VSWR has a range of −∞ ≤ VSWR ≤ ∞.

      

     (Yes/No)

322. The input current in a matched line is 50 mA and the load current is is 1 km long, attenuation in Nepers is
     1. 3.9 NP
     2. 39 NP
     3. − 39 NP
     4. − 39 mNP
323. At low frequencies, Z₀ of a transmission line is
     1. 
     2. 
     3. 
     4. 
324. At high frequencies Z₀ of a transmission line is
     1. 
     2. 
     3. 
     4. 
325. Unit of phase constant is
     1. rad/m
     2. m
     3. degrees
     4. rad/m²
326. At LF and VLF, polarisation often used is
     1. vertical
     2. horizontal
     3. theta
     4. elliptical
327. dB_i means power gain of the antenna in dB relative
     1. dipole
     2. isotropic antenna
     3. dish
     4. horn
328. dB_m means power gain compared to
     1. 1 W
     2. 1 μW
     3. 1 mW
     4. 1 MW
329. If the signal level is 1 mW, power gain is
     1. 0 dBm
     2. 1 dBm
     3. 10^-3 dBm
     4. 10 dBm
330. Whip antenna has a physical length of
     1. 
     2. 
     3. 
     4. λ
331. For a 300Ω antenna operating with 5 A of current, the radiated power is
     1. 7500 W
     2. 750 W
     3. 75 W
     4. 7500 mW
332. Effective area of antenna is a function frequency.

      

     (Yes/No)

333. Antenna used in mobile communications is
     1. whip antenna
     2. dipole
     3. dish
     4. horn
334. Half-power beamwidth of a dish antenna is
     1. 70λ/D
     2. 70D/λ
     3. 7D/λ
     4. 7λ/D
335. If a current element is z-directed, vector magnetic potential is
     1. x-directed
     2. y-directed
     3. θ-directed
     4. z-directed
336. If vector magnetic potential has only A_Z, E_ϕ is ________.
337. Radiation resistance of a current element is
     1. 
     2. 80Ω
     3. 80π² Ω
     4. 
338. Radiation resistance of quarter wave monopole is ________.
339. Directional pattern of a short dipole in the horizontal plane is a ________.
340. Directional pattern of a horizontal half wave centre fed dipole is ________.
341. Effective length of a dipole is always ________ than the actual length.
342. The directivity of half wave dipole is ________.
343. The directivity of current element is ________.
344. Effective area of a Hertzian dipole operating at 100 kHz is ________.
345. FCC means
     1. Federal Communication Council
     2. Foreign Communication Council
     3. Fixed Communication Council
     4. France EC
346. VDE is EMC standard of
     1. USA
     2. India
     3. France
     4. Germany
347. Grounding a conductor will ________ the charge.
348. EMP is created by ________.
349. Shielding is one of the popular methods for ________.
350. The average incident radiation power density should not exceed ________ for human exposures greater than 30 seconds.
351. The unit of self-reaction is ________.