41. The Bragg’s diffraction equation is given by :
(a) sin θ= nλ/ 2d
(b) sin θ= n/2dλ
(c) sin θ= 2dnλ
(d) sin θ= 2(n–λd)
42. The donor impurity must have only ……. valence electrons.
(a) 2
(b) 3
(c) 4
(d) 5
43. The Miller indices of the diagonal plane of a cube are :
(a) 0 1 0
(b) 1 1 0
(c) 0 0 1
(d) 1 1 1
44. One angstrom is equal to :
(a) 10^–9 metre
(b) 10^–11 metre
(c) 10^–10 metre
(d) 10^–12 metre
45. Which one of the following materials does not have a covalent bond ?
(a) Silver
(b) Silicon
(c) Organic polymer
(d) Diamond
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