Solid State Physics-Lattice Vibrations and Thermal Properties of Solid (GATE Physics): Questions 1 - 2 of 2

Get 1 year subscription: Access detailed explanations (illustrated with images and videos) to 290 questions. Access all new questions we will add tracking exam-pattern and syllabus changes. View Sample Explanation or View Features.

Rs. 200.00 or

Question number: 1

» Solid State Physics » Lattice Vibrations and Thermal Properties of Solid

Appeared in Year: 2015

Short Answer Question▾

Write in Short

The dispersion relation for phonons in a one dimensional monatomic Bravais lattice with lattice spacing a and consisting of ions of masses M is given by,

ω(k)=2CM[1cos(ka)]

Where ω is the frequency of oscillation, k is the wavevector and C is the spring constant. For the long wavelength modes (λa) , the ratio of the phase velocity to the group velocity is ________.

Question number: 2

» Solid State Physics » Lattice Vibrations and Thermal Properties of Solid

Appeared in Year: 2013

Match List-Ⅰ List-Ⅱ▾

Question

Group I contains elementary excitation in solids. Group II gives the associated fields with these excitations. MATCH the excitations with their associated field and select your answer as per codes given below.
List-Ⅰ (Group I) List-Ⅱ (Group II)

(A)

Polaron

(i)

Elastic wave

(B)

Phonon

(ii)

Electron + elastic deformation

(C)

Polariton

(iii)

Photon + lattice vibration

(D)

Plasmon

(iv)

Collective electron oscillations

Choices

Choice (4) Response
  • (A)
  • (B)
  • (C)
  • (D)
a.
  • (iv)
  • (iii)
  • (ii)
  • (i)
b.
  • (ii)
  • (i)
  • (iii)
  • (iv)
c.
  • (iii)
  • (i)
  • (ii)
  • (iv)
d.
  • (iii)
  • (ii)
  • (i)
  • (iv)

Sign In