Solid State Physics - Study Mode
[#41] A linear diatomic lattice of lattice constant a with masses M and m (M > m) are coupled by a force constant C. The dispersion relation is given by $${omega ^2} = Cleft( {frac{{M + m}}{{Mm}}}
ight) pm {left[ {{C^2}{{left( {frac{{m + m}}{{Mm}}}
ight)}^2} - frac{{4{C^2}}}{{Mm}}{{sin }^2}frac{{ka}}{2}}
ight]^{frac{1}{2}}}$$ Which one of the following statements is incorrect?
Correct Answer
(C) The dispersion of frequency in the optical branch is smaller than that in the acoustic branch
[#42] The Hall coefficient R H of sodium depends on
Correct Answer
(C) the charge carrier density only
[#43] Which one of the following axes of rotational symmetry is not permissible in single crystals?
Correct Answer
(D) Five-fold axis
[#44] The potential in a divalent solid at a particular temperature is represented by a one-dimensional periodic model. The solid should behave electrically as
Correct Answer
(B) a conductor
[#45] The c/a ratio for an ideal hexagonal closed packed structure is
Correct Answer
(D) $$sqrt {frac{8}{3}} $$