Electromagnetic Fields Mid - I, September - 2014

1.Force on a stationary or moving electric charge Q in electric field E is given by
  • E/Q2
  • EQ
  • E/Q
  • E2/Q
Answer: B
2.The electric flux lines from a charged conducting body such that the angle between the surface of the conductor and the flux line is
  • π / 2
  • π / 3
  • π / 6
  • π / 4
Answer: A
3.The electric potential has
  • Only magnitude
  • only direction
  • neither magnitude nor direction
  • none of the above
Answer: A
4.Potential at a point distance ‘r’ from the dipole varies as
  • 1/r
  • 1/r2
  • 1/r3
  • independent of r
Answer: B
5.For perfect conductors the charge density inside the surface is
  • maximum
  • zero
  • one
  • minimum
Answer: B
6.Capacitance of two concentric conducting spheres of radius ‘a’ and ‘b’ is given by
  • 4πεob
  • 4πεoab/(b-a)
  • 4πεo/b
  • 4πεoa
Answer: B
7.Boundary condition for free space and dielectric is
  • Dn1 – Dn2 = s
  • Dn1 = Dn2
  • En1 – En2 = s
  • none of these
Answer: A
8.A void is formed in a parallel plate capacitor which is filled with a dielectric of εr = 4. If the electric stress in the dielectric is 20 KV/cm, then the electric stress in the void is
  • 20 KV/cm
  • 80 KV/cm
  • 5 KV/cm
  • 200 KV/cm
Answer: B
9.If a conductor is lying on the z-axis, to find the magnetic field in cylindrical coordinates around the conductor, the magnetic field should be along
  • az
  • ar
  • aθ
  • ax
Answer: C
10.The field intensity due to infinite line current is inversely proportional to
  • Flux
  • distance
  • charge
  • square of distance
Answer: B
11.Magnetic field intensity in terms of magnetic flux density is given by ______________.
Answer: H = B/
12.The equation that indicates that the magnetic flux lines are continuous is ___________.
Answer:  . B = 0
13.Ohm’s law in point form is __________________.
Answer: J = E
14.Boundary conditions for a perfect dielectric material is derived from ________________ law.
Answer: Gauss’s law
15.The poisson’s equation for the potential V is _________________.
Answer: 2V = v/
16.For a given dipole, if the angle between p and E is zero, then the torque on the dipole is ____________.
Answer: Zero
17.In an electric field, the maximum value of rate of change of potential with respect to the distance is called ____________________________.
Answer: Potential gradient
18.Electric flux originates at ________________ and terminates at ____________________.
Answer: +ve charge, -ve charge
19.Gauss’s law in integral form is ___________________________.
Answer: Qenc = §D.dS
20.The unit of dipole moment is ___________________.
Answer: C-m