14 questions
Which of the following is true about the charge acquired by P type semiconductor?
positive
negative
neutral
depends on concentration of p impurities
to get a n-type semiconductor from silicon it should be dopped with a substance with valence
2
1
3
5
the total number of tetrahedral voids in the face centred unit cell is
6
8
10
12
which of the following point defects are shown by AgBr(s) Crystal
A-Schottky defect
B- Frankel defect
C-metal excess defect
C-metal deficiency defect
A&B
in which pair most efficient packing is present
hcp and bcc
hcp and ccp
bcc and ccp
bcc and simple cubic cell
the percentage of empty space in a body-centered cubic arrangement is
74
68
32
26
which of the following statement is not true about the hexagonal close packing
the coordination number is 12
it has 74% packing efficiency
tetrahedral void of the second layer are covered by the share of the third layer
in this arrangement spheres of the fourth layer are exactly aligned with those of the first layer
in which of the following structures coordination number for cation and anion in the packed structure will be same
Cl negative ions form fcc lattice and Na positive ions occupy all octahedral voids of the unit cell
Ca2 positive from fcc lattice and F negative ions occupy all the 8 tetrahedral voids of the unit cell
O2 negative ions from fcc lattice and Na positive ions occupy all the 8 tetrahedral volds of the unit cell
S2 negative ions from fcc lattice and Zn two positive ions go into alternate tetrahedral was of the unit cell
what is the coordination number in a square close packing structure in two dimensions
2
3
4
6
which kind of defects are introduced by doping
dislocation defect
Schottkey defect
frenkel defect
electronic defect
Silicon doped with electron rich impurity forms
P type semiconductor
n type semiconductor
Intrinsic semiconductor
Insulator
which of the following statement is not true
paramagnetic substance are weakly attracted by magnetic field
ferromagnetic substances cannot be magnetized permanently
the domains in antiferromagnetic substances are oppositely oriented with respect to each other
pairing of electrons cancel their magnetic moment in the diamagnetic substances
which of the following is not true about the ionic solids
bigger and form the close packed structure
smaller ions occupy either the tetrahedral or the octahedral voids depending upon their size
occupation of all the voids is not necessary
the fraction of octahedral or tetrahedral voids occupied depends upon the radii of the Ion occupy the voids
a feromagnetic substances becomes a permanent magnet when it is placed in a magnetic field because
all the domen's get oriented in the direction of magnetic field
all domains get oriented in the direction opposite to the direction of magnetic field
domain get oriented randomly
domains are not affected by magnetic field