Solid State Physics-Mobility and Effective Mass (GATE Physics): Questions 1 - 4 of 4

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Question number: 1

» Solid State Physics » Mobility and Effective Mass

Appeared in Year: 2016

Short Answer Question▾

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The energy vs wave vector (Ek) relationship near the bottom of a band for a solid can be approximation as E=A(ka)2+B(ka)4 , where the lattice constant a=2.1 . The values of A and B are 6.3×1019J and 3.2×1020J , respectively. At the bottom of the conduction band, the ratio of the effective mass of the electron to the mass of fee electron is _ . (Give your answer up to two decimal placed)

(Take =1.05×1034Js, mass of free electron =9.1×1031kg )

Passage

The tight binding energy dispersion (Ek) relation for electrons in a one – dimensional array of atoms having lattice constant a and total length L is, E=E0β2γcos(ka) ; where E0,β and γ are constants and k is the wave – vector.

Question number: 2 (1 of 1 Based on Passage) Show Passage

» Solid State Physics » Mobility and Effective Mass

Appeared in Year: 2011

MCQ▾

Question

The effective mass of electrons in the band is given by,

Choices

Choice (4) Response

a.

2γa2cos(ka)

b.

2γa2sin(ka)

c.

22γa2cos(ka)

d.

22γa2sin(ka)

Passage

The atomic density of a solid is 5.85×1028m3 . Its electrical resistivity is 1.6×108Ωm . Assume that electrical conduction is described by the Drude model (classical theory), and that each atom contributes one conduction electron.

Question number: 3 (1 of 2 Based on Passage) Show Passage

» Solid State Physics » Mobility and Effective Mass

Appeared in Year: 2007

MCQ▾

Question

The drift mobility (in m2V1s1 ) of the conduction electrons is –

Choices

Choice (4) Response

a.

7.63×103

b.

6.67×103

c.

6.67×106

d.

7.63×106

Question number: 4 (2 of 2 Based on Passage) Show Passage

» Solid State Physics » Mobility and Effective Mass

Appeared in Year: 2007

MCQ▾

Question

The relaxation time (mean free time), in seconds, of the conduction electrons is –

Choices

Choice (4) Response

a.

2.84×1012

b.

2.64×1011

c.

3.79×1014

d.

3.98×1015

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