Electromagnetic Field Theory
Due to which of the following reasons a lightning conductor on top of a building is made into a pointed spike?

None of these
Charge per unit area becomes very high for lightening to discharge
Dust particles may not accumulate
Rain drops may not collect

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Electromagnetic Field Theory
If an electric current carrying coil is placed in a uniform magnetic field in the direction of magnetic induction, then

 the net force and torque are both finite.
 the net force is zero but torque is finite.
 the net force is finite but torque is zero.
 the net force and torque on the coil are both zero.

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Electromagnetic Field Theory
The effective reactance of an inductive coil

 increases because of stray capacitance as the frequency increases.
 decreases because of stray capacitance as the frequency increases.
 remains same irrespective of the frequency.
 none of these.

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Electromagnetic Field Theory
Two spheres of radius r1 and r2 are connected by a conducting wire. Each of the spheres has been given a charge Q. Now

 larger sphere will have greater potential.
 smaller sphere will have zero potential.
 larger sphere will have smalled potential.
 both of sphere will have same potential.

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Electromagnetic Field Theory
A long wire composed of a smooth round conductor runs above and parallel to the ground (assumed to be a large conducting plane). A high voltage exits between the conductor and the ground. The maximum electric stress occur at

 The upper surface of the conductor.
 The lower surface of the conductor.
 The ground surface.
 Midway between the conductor and ground.

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