JEE PYQ: Solid State Question 1
Question 1 - 2021 (16 Mar Shift 1)
A certain element crystallises in a bcc lattice of unit cell edge length $27 \text{ \AA}$. If the same element under the same conditions crystallises in the fcc lattice, the edge length of the unit cell in $\text{\AA}$ will be ___. (Round off to the Nearest Integer).
[Assume each lattice point has a single atom]
[Assume $\sqrt{3} = 1.73$, $\sqrt{2} = 1.41$]
Show Answer
Answer: 33
Solution
For BCC, $\sqrt{3},a = 4r$, so $r = \dfrac{\sqrt{3}}{4} \times 27$. For FCC, $a = 2\sqrt{2},r = 2\sqrt{2} \times \dfrac{\sqrt{3}}{4} \times 27 = \dfrac{\sqrt{3}}{\sqrt{2}} \times 27 = 33$.
BETA
