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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Q. The real part of complex dielectric constant and tanδ for a dielectric are 2.1 and 5 x 10¯⁴ at 100 Hz respectively. The imaginary part of dielectric constant at 100 Hz is

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Q. A copper atom is neutral. Its core has a net charge of

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Q. As the temperature of semiconductor is increased

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Q. In anti-ferromagnetic materials, the graph of susceptibility versus temperature shows a sharp maximum at a certain temperature. This temperature is known as

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Q. The wavelength of light emitted by GaAs laser is 8670 x 10¯¹ᴼ m. If h = 6.626 x 10¯³⁴ Js, velocity of light = 3 x 10⁸ m/s and eV = 1.602 x 10¯¹⁹ J, the energy gap in GaAs is

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Q. Diamagnetic materials do not have permanent magnetic dipoles.

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Q. A piece of copper and another piece of Germanium are cooled from 30°C to 80 K. The resistance of

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Q. The dipole moment per unit volume P as a function of E for an insulator is

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Q. A good dielectric should have

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Q. Magnetic hysteresis phenomenon is explained by

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Q. The relation between thermal conductivity K (W/m/°C), heat flow density Q (watt/m²) and dT/dx (°C per metre) is

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