GATE Physics: Questions 277 - 279 of 622

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Question number: 277

» Solid State Physics » Defects in Crystals

Appeared in Year: 2010

MCQ▾

Question

The Bloch theorem states that within a crystal, the wavefunction, Equation of an electron has the from –

Choices

Choice (4) Response

a.

Equation where Equation , Equation is a lattice vector and Equation is an arbitrary vector

b.

Equation , where Equation is an arbitrary function and Equation is an arbitrary vector

c.

Equation where Equation is an arbitrary function and Equation is a reciprocal lattice vector

d.

Equation where Equation , Equation is a lattice and Equation is a reciprocal lattice vector

Question number: 278

» Mathematical Physics » Elementary Ideas About Tensors » Covariant and Contravariant Tensor

Appeared in Year: 2010

MCQ▾

Question

Consider an anti – symmetric tensor Equation with the indices Equation and Equation running from Equation to Equation . The number of independent components of the tensor is –

Choices

Choice (4) Response

a.

3

b.

10

c.

6

d.

9

Question number: 279

» Atomic and Molecular Physics » Electronic Transition in Diatomic Molecules

Appeared in Year: 2010

MCQ▾

Question

Two states of an atom have definite parities. An electric dipole transition between these states is

Choices

Choice (4) Response

a.

Allowed if both the states have even parity

b.

Allowed if both the states have odd parity

c.

Not allowed unless a static electric field is applied

d.

Allowed if the two states have opposite parities

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