CSIR Physical Sciences: Questions 352 - 355 of 389

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Question number: 352

» Thermodynamic and Statistical Physics » Maxwell Relations

Appeared in Year: 2012

MCQ▾

Question

The energy required to create a lattice vacancy in a crystal is equal to 1eV . The ratio of the number densities of vacancies n1200Kn300K , when crystal is equilibrium at 1200 K and 300 K, respectively, is approximately, (June)

Choices

Choice (4) Response

a.

exp(15)

b.

exp(30)

c.

exp(15)

d.

exp(30)

Question number: 353

» Classical Mechanics » Special Theory of Relativity » Relativistic Kinematics

Appeared in Year: 2011

MCQ▾

Question

Two gravitating bodies A and B with masses mA and mB , respectively, are moving I circular orbit. Assume that mBmA and let the radius of the orbit of body A be RA . If the body A is losing mass adiabatically, its orbital radius RA is proportional to –

(June)

Choices

Choice (4) Response

a.

1mA

b.

1mA2

c.

mA2

d.

mA

Question number: 354

» Mathematical Methods of Physics » Linear Ordinary Differential Equations of First & Second Order

Appeared in Year: 2011

MCQ▾

Question

Let x1(t) and x2(t) be two linearly independent solutions of the differential equation, d2xdt2+2dxdt+f(t)x=0 and let W(t)=x1(t)dx2(t)dtx2dx1(t)dt . If W(0)=1 , then W(1) is given by, (December)

Choices

Choice (4) Response

a.

1

b.

e-2

c.

1e

d.

1e2

Question number: 355

» Thermodynamic and Statistical Physics » Fermi Gases

Appeared in Year: 2011

MCQ▾

Question

The energy levels of electrons of mass ‘m’ and charge ‘e’ confined in an area A in the xy – plane with a uniform magnetic field B applied in the z – direction are given by En=(n+12)eBmc,n=0, 1,2, the degeneracy of each level is eBAc . The lowest level is completely filled and the others are empty. The Fermi energy 2N2πmA , where, N is the total number of electrons, is – (December)

Choices

Choice (4) Response

a.

Coincident with the n=0 level

b.

Midway between the n=0 and the n=1 levels

c.

Midway between the n=1 and the n=2 levels

d.

Coincident with the n=1 level

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