Which of the following has bcc structure?
The correct answer is: CsCI
If is wave vector of incident X-ray and be the reciprocal lattice vector then condition for Bragg reflection is given by :
Correct Answer :- b
Explanation : Bragg reflection or diffraction occurs when light waves are incident on an ultrasonic wave with a comparable wavelength. The light is reflected in a specular fashion by the ultrasonic grating, and undergoes constructive interference in accordance with Bragg's law.
Let be the scattered wave vector, then from Ewald construction :
K' = K - G....(i)
Since, for elastic scattering, there will be no change in the magnitude of the vector i.e.
|K| = K' = 2pi/λ
Now squaring (i),
K2 = K2 + G2 - 2K . G
G2 = 2K . G
Which of the following lattices has the least packing fraction?
packing fraction of simple cubic = 52% packing fraction of bee = 68%
packing fraction of fee = 74%
packing fraction of diamond = 34%
The correct answer is: diamond
The radii of Cs and Cl are r1 and r2 respectively. Which of the following gives the lattice constant of CsCI if it is crystalized in bcc structure :
For bcc structure ,
The correct answer is:
A lattice is characterized by following primitive vectors
Hence, lattice is bcc with edge π
The correct answer is: bcc with cube edge π
What is the reciprocal lattice to simple cubic lattice?
Primitive translation Vectors of simple cubic lattice may be written as :
Then primitive translation vector of reciprocal lattice is
Hence, the reciprocal lattice is itself a simple cubic lattice with lattice constant
The correct answer is: simple cubic
A body centred cubic lattice has edge a. Edge of its primitive cells will be :
from figure, AB = a
The correct answer is:
The primitive translation vectors of the fcc lattice are
The volume of the primitive cell of reciprocal lattice is :
The correct option is D
The primitive translation vector of the reciprocal lattice to the above lattice be calculated as :
volume of the reciprocal lattice is:
The correct answer is, 4(2π/a)3
The positions of number of nearest neighbours in a unit cell of bcc structure is given by:
Nearest neighbour to an atom (say at origin) is the atom present is the centre of the
at point P and the position of P can be =
The correct answer is: =
What is the second nearest neighbour distance in a face centered cubic whose conventional unit cell parameter is a?
Here AC is the nearest distance while AB or AD forms the nearest neighbour distance which is equal to ' a '.
The correct answer is: a