1)In a solid AB of NaCl structure. A atoms occupy the corners of the cubic unit cell. If all the the corner atoms are removed then the formula of the unit cell,
2)The p type semiconductors is obtained when Si is doped with (a)Al (b)Ga [ p type semiconductors are made when elements are doped with the group 13 elements, here in options both are from 13 group & answer given is Ga, why cant (a) be the correct answer too since it also belongs to 13th group]
3)Schottky defect is due to
a)missing of electron
b)missing of atom
I have read it ts due to missing of atoms, but the option (a) is given correct.
4)Which of the following crystals has lagrest lattice energy & why?
(a)KCl (b)RbI (c)MgO (d) NaF
5)Metallic rhodium crystallizes in a fcc lattice with a unit cell edge length of 3.803 angstrom. Calculate the molar volume of rhodium including the empty spaces.
11) A3B4
2) it is absoloutely clear that it can doped with both but preferable is alluminium due to less size difference.....
3)it is due to missing of cations and anions
4) c
5) put 4r=3.803 cal. r now apply 4nr33=x
now cal. (4.803)3x 26% = y
x+y would be the answer...
11thanks Nihal
for the 2nd question the answer given is galium and not aluminium.
what's the reason for the answer of the 4th question?
1THE CONRIBUTION OF ONE ATOM DECREASES BY REMOVING ALL THE CORNER ATOMS . IF IT WOULD NOT BE REMOVED THEN A4B4 BUT NOW 6X12=3 ATOMS WHERE 6 ARE THE FACE ATOMS EACH HAVING CONTRIBUTION 1/2 IN A UNIT CELL AND B4 BECAUSE B IS THE CATION WHICH OCCUPY 4 TETRAHEDRAL VOIDS...