Q. Which of the following is used in lightning arresters?

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Q. High frequency inductors and capacitors are commonly plated with silver. The main purpose of this is to

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Q. In its lowest state, the electron is bound to the field of proton by an energy equal to

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Q. In a ferromagnetic material, the internal field seen by a dipole is

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Q. Consider the following statement: In case of a superconductor

1. B = 0
2. μᵣ is high
3. diamagnetism is high
4. transition temperature varies with isotopic mass.

Of the above statements

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Q. Assertion (A): In liquids and glassy substances, dielectric losses occur.

Reason (R): The orientation polarization in many substances is frequency dependent.

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Q. A single layer air cored coil has n turns and inductance L. If a new coil is formed by having 2n turns while keeping the coil length and diameter the same, the new inductance is

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Q. The colour code on a carbon resistor is yellow-violet-orange. The value of resistance is

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Q. A leaky dielectric has ∈ᵣ = ∈ᵣ' - j∈ᵣ". If a field E is applied, the current component in phase with E is proportional to ∈ᵣ".

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Q. Assertion (A): In ionic dielectrics, P = Pe + Pi.

Reason (R): In ionic crystals, permanent electric dipole moment is zero.

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Q. The current flow in a semiconductor is due to

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Q. Assertion (A): Relative permittivity is determined by the atomic structure of the material.

Reason (R): Absolute permittivity is determined by the atomic structure of the material.

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Q. Eddy current loss is

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Q. Some ceramic materials become superconducting

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Q. Assertion (A): Doping level in extrinsic semiconductors is very small.

Reason (R): Additional of impurity in the ratio of 1 part in 108 parts increases the number of charge carriers by about 20.

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Q. The core of an atom consists of

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Q. Assertion (A): Copper is a good conductor of electricity.

Reason (R): Copper has a face centred cubic lattice.

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Q. When a dielectric is subjected to an electric field E, each volume element of dielectric can be considered to be carrying an electric dipole moment.

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Q. A dielectric of relative permittivity ∈ᵣ is subjected to a homogeneous electric field E. The dipole moment P per unit volume is given by

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Q. Which of these has the highest dielectric strength?

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