ECE :: Materials and Components
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An electron in a metal suffers collision and if the probability of it being scattered over an angle dθ is 2p P(θ) sin θ dθ where P(θ) is an arbitrary function of scattering angle θ, then
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For an insulating material, dielectric strength and dielectric losses should be
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Consider the following statements
- An iron cored choke is non linear and passive device.
- A carbon resistor kept in sunlight is a time invariant and passive device.
- A dry cell is a time varying and active device.
- An air capacitor is time invariant and passive device.
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Some ceramic materials become superconducting
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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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The core of an atom consists of
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Assertion (A): Copper is a good conductor of electricity.
Reason (R): Copper has a face centred cubic lattice.
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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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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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