CSIR Physical Sciences: Questions 228 - 230 of 389

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Question number: 228

» Atomic & Molecular Physics » Diatomic Molecules » Vibrational

Appeared in Year: 2013

MCQ▾

Question

The phonon dispersion for the following one – dimensional diatomic lattice with masses M1 and M2 (as shown in figure)

Diagram of phonon dispersion

Diagram of Phonon Dispersion

In figure the phonon dispersion for the following one – dimensional diatomic lattice with masses M1 and M2.

is given by, ω2(q)=K(1M1+1M2)[1±14M1M2M1+M2sin2(qa2)]

where a is the lattice parameter and K is the spring constant. The velocity of sound is – (June)

Choices

Choice (4) Response

a.

K(M1+M2)2M1M2a

b.

K(M1+M2)M1M2a

c.

K2(M1+M2)a

d.

KM1M22(M1+M2)3a

Question number: 229

» Quantum Mechanics » Time Dependent Perturbation Theory

Appeared in Year: 2014

MCQ▾

Question

The ground state eigenfunction for the potential V(x)=δ(x) , where δ(x) is the delta function, is given by ψ(x)=Aeα x , where A and α>0 are constants. If a perturbation H=bx2 is applied, the first order correction to the energy of the ground state will be – (June – 2014)

Choices

Choice (4) Response

a.

bα2

b.

2bα2

c.

b2α2

d.

b2α2

Question number: 230

» Electromagnetic Theory » Electromagnetic Induction

Appeared in Year: 2013

MCQ▾

Question

The electric field of an electromagnetic wave is given by, E=E0cos[π(0.3x+0.4y1000t)]k^ . The associated magnetic field B is (December – 2013)

Choices

Choice (4) Response

a.

102E0cos[π(0.3x+0.4y1000t)](3i^+4j^)

b.

104E0cos[π(0.3x+0.4y1000t)](4i^3j^)

c.

103E0cos[π(0.3x+0.4y1000t)]k^

d.

E0cos[π(0.3x+0.4y1000t)](0.3i^+0.4j^)

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