8. For electrons in a metallic solid, a. If an electric field is applied to a me
ID: 2303590 • Letter: 8
Question
8. For electrons in a metallic solid, a. If an electric field is applied to a metal a. very few electrons are excited into the conduction band. b. electrons having energies near the Fermi energy require only a small amount of additional energy from the applied field to reach nearby empty energy states. c. electrons having energies near the bottom of the band require only a small amount of additional energy from the applied field to reach nearby empty energy states. d. the principal mode of conduction is through the motion of holes in the filled part of the band e. the Fermi energy Ey becomes equal to the applied electric field E b. To find the number of electrons per unit volume with energy between E and E+ dE we must multiply the number of allowed states per unit volume with energy E by a. the probability that a state is unoccupied,- b. the probability that a state is occupied,-B c. the probability that a state is unoccupied, d. the probability that a state is occupied, e. dE alone c. An energy band in a solid consists of a. an infinite number of levels, with each level corresponding to a point in a box. b. a large number of energy levels so closely spaced that they may be regarded as a continuous band. c. an infinite number of wave functions, with each wave function corresponding to a point in a box. d. a large number of electrons so closely spaced that they may be regarded as a continuous band of electric charge. e. an infinite number of electrons, with each electron corresponding to a point in a box.Explanation / Answer
8.a - answer (b), since fermi energy is nothing but the difference between highest occupied ( top of valence band ) and lowest occupied (bottom of conduction band ) single particle state and this one is the smallest energy difference compare to any other.
8.b - answer (b), electron is a fermion, follow fermi dirac distribution law. so, to calculate number of electron per unit volume we must have multiply no. of allowed state /volume with probability of how many electron occupy those state.
8.c - answer (b), energy band is nothing but the range of energies assosiated with quantum state of electron in crystalline solid and in that there is large number of energy level group togather with very small separation.
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