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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Q. For an insulating material, dielectric strength and dielectric losses should be

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Q. Consider the following statements

1. An iron cored choke is non linear and passive device.
2. A carbon resistor kept in sunlight is a time invariant and passive device.
3. A dry cell is a time varying and active device.
4. An air capacitor is time invariant and passive device.

Of these statements

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Q. The direction of force an a conductor carrying current and lying in a magnetic field can be found by using

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Q. Assertion (A): Rochelle salt and Barium titanate are both ferroelectric.

Reason (R): Ferroelectric materials exhibit hysteresis effect.

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Q. The units for electric dipole moment are

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Q. The temperature coefficient of resistivity of semiconductors is

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Q. Which of the following is used in automatic control of street lights?

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Q. Assertion (A): In an intrinsic semiconductor J = (μn x μp)eni.

Reason (R): Intrinsic charge concentration ni at temperature T is given by ni² = A₀ T³ e^(-EG0/kT).

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Q. When the atom of rare gas is placed in an electric field the nucleus shifts from the centre of electron cloud by an amount x. If the radius of electron cloud is R, then

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Q. Macroscopic quantities of a given material

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Q. For a superconductor, the relative permeability is

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Q. The relative permeability of a ferromagnetic material is

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Q. Assertion (A): Intrinsic resistivity of silicon is lower than that of germanium.

Reason (R): Magnitude of free electron concentration in germanium is more than that of silicon.

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Q. The units for ∈ᵣ are

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