AP EAMCET201920 Apr 2019Evening ShiftChemistrySolid StateActual
Which one of the following statements is not correct?
Options
- ASchottky defect in ionic solids does not change the density of the crystal
- BPacking efficiency is the percentage of total space filled by the particles
- CIn body centered cubic unit cell, the relationship between atomic radius (r) and the edge length (a) is, r= 3
- DPhotovoltaic cell is used for conversion of light energy into electrical energy
Correct answer
A. Schottky defect in ionic solids does not change the density of the crystal
Step-by-step solution
(a) Schottky defect is a type of point defect in a crystal lattice in which ions leaves their lattice sites leaving vacancy. Hence, it decreases the density of crystal. (b) Packing efficiency is percentage value of total space filled by the particles. Packing efficiency = Volume of atom occupied Total volume of unit cell 100 (c) In bcc crystal lattice aligned R+2 R+R & = 3 a 4 R & = 3 a R & = 3 4 a aligned (d) Photovoltaic cell is used for conversion of light energy into electrical energy. Hence, option (a) is inco