GATE Physics: Questions 18 - 22 of 378

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Question number: 18

» Quantum Mechanics » Angular Momentum and Spin

Appeared in Year: 2014

Short Answer Question▾

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A hydrogen atom is in the state ψ=821ψ20037ψ310+421ψ321

Where n,l,m in ψnlm denote the principal, orbital and magnetic quantum numbers, respectively. If L is the angular momentum operator, the average value of L2 is________ 2 .

Question number: 19

» Solid State Physics » Elements of Crystallography

Appeared in Year: 2015

Short Answer Question▾

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The lattice parameters a,b,c of an orthorhombic crystal are related by a=2b=3c . In units of a , the inter-planar separation between the (110) planes is ________ (up to three decimal places)

Question number: 20

» Electronics » Semiconductor Devices

Appeared in Year: 2015

Short Answer Question▾

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The bad gap of an intrinsic semiconductor is Eg=0.72eV and mh=7me . At 300 K, the Fermi level with respected to the edge of the valence band (in eV) is at ________ (up to three decimal places)

[kB=1.38×1023JK]

Question number: 21

» Classical Mechanics » Relativistic Kinematics

Appeared in Year: 2014

Short Answer Question▾

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If the half – life of an elementary particle moving with speed 0.9c in the laboratory frame is 5×108s , then the proper half – life is ________ ×108s . (c=3×108ms)

Question number: 22

» Mathematical Physics » Elements of Complex Analysis » Residue Theorem and Applications

Appeared in Year: 2014

MCQ▾

Question

The value of the integral Cz2ez+1dz, Where C is the circle z =4 , is –

Choices

Choice (4) Response

a.

4π2i

b.

2πi

c.

4π3i

d.

2π2i

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