Topic: Electromagnetic (Test 1)

Topic: Electromagnetic
Q.1
Consider a straight, infinitely long, current carrying conductor lying on the z-axis. Which one of the following plots (in linear scale) qualitatively represents the dependence of Hϕ on r , where Hϕ is the magnitude of the azimuthal component of magnetic field outside the conductor and r is the radial distance from the conductor ?
A.
B.
C.
D.
Answer : Option C
Explaination / Solution:
No Explaination.

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Q.2
Thefield (in A/m) of a plane wave propagating in free space is given by
The time average power flow density in Watts is
A. η0/100
B. 100/η0
C.
D. 50/η0
Answer : Option D
Explaination / Solution:

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Q.3
In cylindrical coordinate system, the potential produced by a uniform ring charge is given by φ = f(r, z), where f is a continuous function of r and z. Let  be the resulting electric field. Then the magnitude of ∇ ×
A. increases with r.
B. is 0.
C. is 3.
D. decreases with z.
Answer : Option B
Explaination / Solution:

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Q.4
A vector is given by  Which one of the following statements is TRUE?
A. is solenoidal, but not irrotational
B. is irrotational, but not solenoidal
C. is neither solenoidal nor irrotational
D. is both solenoidal and irrotational
Answer : Option A
Explaination / Solution:

Given vector,

If divergence  then vector  is solenoidal. So, we obtain

Hence, it is solenoidal.
Again, if curl then  is irrotational. So, we obtain

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Q.5
Two electric charges q and −2q are placed at (0,0) and (6,0) on the x-y plane. The equation of the zero equipotential curve in the x-y plane is
A. x = −2
B. y = 2
C. x2 + y2 = 2
D. (x+2)2 + y2 = 16
Answer : Option D
Explaination / Solution:

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Q.6
For static electric and magnetic fields in an inhomogeneous source-free medium, which of the following represents the correct form of Maxwell’s equations ?
A.
B.
C.
D.
Answer : Option D
Explaination / Solution:

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Q.7
The value of the line integral

along a path joining the origin (0, 0, 0) and the point (1, 1, 1) is
A. 0
B. 2
C. 4
D. 6
Answer : Option B
Explaination / Solution:

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Q.8
Two electrodes, whose cross-sectional view is shown in the figure below, are at the same potential. The maximum electric field will be at the point

A. A
B. B
C. C
D. D
Answer : Option C
Explaination / Solution:

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Q.9
The force on a point charge +q kept at a distance d from the surface of an infinite grounded metal plate in a medium of permittivity 𝜖 i
A. 0
B.  away from the plate
C.   towards the plate
D.   towards the plate
Answer : Option C
Explaination / Solution:

Consider the point charge +q and infinite surface as shown below.

We can replace the image charge by a negative equivalent charge -q placed at 2d distance from +q charge

Hence, the force experienced by +q charge is

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Q.10
The value of the integral of the function g(x,y) = 4x3 + 10y4 along the straight line segment from the point (0,0) to the point (1,2) in the x - y plane is
A. 33
B. 35
C. 40
D. 56
Answer : Option A
Explaination / Solution:

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