Q. At a very low temperature, a semiconductor

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Q. The colour code on a carbon resistor is red-red-black-silver. The value of resistor is

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Q. Some typical examples of macroscopic quantities are

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Q. The temperature coefficient of a thermistor

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Q. Assertion (A): Helium, Argon and Neon are gaseous at room temperature.

Reason (R): The atoms in Helium, Argon and Neon are chemically extremely inactive.

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Q. Assertion (A): For most metals, Fermi energy EF is less than 10 eV.

Reason (R): Fermi level of a metal is given by EF = 3.64 x 10^-19 (n)^2/3 where n is number of free electrons/m³ of metal.

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Q. The capacitance of an insulated conducting sphere of radius R in vacuum is

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Q. The transition of electron from energy level W1 to W2 is associated with emission or absorption of electro magnetic radiation of frequency f such that

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Q. Even at room temperature, an intrinsic semiconductor has some holes. These holes are due to

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Q. If a capacitor C having selectivity factor Q is scaled down in all its dimensions by a factor K without any altering the dielectric material, the new capacitor will have capacitance and selectivity as

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Q. The hysteresis loss is

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Q. Assertion (A): For a magnetic material M = (μᵣ - 1) H, where M is magnetic dipole moment/m³, H is field intensity A/m and μᵣ is relative permeability.

Reason (R): μᵣ can have any value from 0 to hundreds of thousands.

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Q. As regards ∈₀ and ∈ᵣ (absolute and relative permittivity)

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Q. In carbon resistor colour code, if the third band is of silver, it indicates

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Q. In a metal, the drift velocity of electrons in the presence of a electric field E is

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Q. At a temperature of about 1 K, aluminium is a

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Q. If v is the velocity of electron, tc is the average time between collisions, the mean free path λ = vtc.

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Q. A liquid has N permanent dipoles μᵨ per unit volume and has been subjected to dc field for a long time such that orientation polarization is P₀. At t = 0, the field is suddenly removed, then polarization

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Q. Assertion (A): Orbital magnetic moment of an electron in an atom is of the order of 1 Bohr magneton.

Reason (R): 1 Bohr magneton = 9.27 x 10^-24 A/m².

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Q. As per Bohr's postulate, only those circular orbits are stable for which the angular momentum is equal to an integer times h/2π .

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