Q. The temperature at which some materials become superconductors is called

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Q. In Fermi-Dirac statistics, the probability of electron occupation of an energy level equal to Fermi level is

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Q. The quantum numbers associated with electron motion are designed as

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Q. The carrier mobility in a semiconductor is 0.4 m²/Vs. Its diffusion constant at 300 K will be (in m²/s)

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Q. Which of these has lowest dielectric strength?

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Q. The maximum temperature limit of class B insulation is

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Q. Resistivity of metals consists of two parts, one part constant and the other temperature dependent.

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Q. The number of valence electrons in germanium atom is

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Q. Assertion (A): ∈₀ has the dimensions of farad per meter.

Reason (R): D = ∈₀∈ᵣ E.

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Q. When temperature is more than ferromagnetic curie temperature, the behaviour of a ferromagnetic material is similar to that of paramagnetic material.

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Q. As regards dielectric constant εr

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Q. A parallel plate capacitor having C = 200 x 10¯¹² F has loss dielectric having tan δ = 4 x 10¯⁴. At an ac voltage of f = 10⁶ Hz and peak value 2 V, the dielectric losses are

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Q. In ferromagnetic materials, the orientation between neighbouring permanent dipoles is parallel.

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Q. Resistivity of copper is lower than that of nickel. When a small percentage of copper is added to nickel, the resistivity

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Q. Lines of magnetic field attract each other.

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Q. In a valence crystal, the valence electrons

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Q. Transformer oil is

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Q. Assertion (A): Drift velocity of electrons is proportional to the applied electric field E.

Reason (R): The average drift velocity per unit field is called mobility.

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Q. The materials having low retentivity are suitable for making

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Q. If ∈ᵣ = ∈ᵣ' - j∈ᵣ" tan δ = ∈ᵣ'/∈ᵣ".

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