TS EAMCET 10-Sep-2020 Shift 2 Solved Paper

∵ For bcc lattice, radius ratio for r+∕r−is 0.7,
i.e. radius ratio of cation by anion ranges from 0.732 to 1.0. Also, for bcc r−ions are at corners,
Thus, ‌‌4×r−=√3a‌‌(∵√3a=1.7×200)
(where, a= edgelength ) and 4×r−=1.7×200
r−=‌

1.7×200

4

=85pm
∴‌‌‌

r+

r−

=‌

70

85

=0.82, which is close to 0.7.
Hence, option (a) is the correct answer.