Iron exhibits bcc structure at room temperature. Above 900°C, it transforms to fcc structure. The ratio of density of iron at room temperature to that at 900°C (assuming molar mass and atomic radii of iron remains constant with temperature) is:

Q. Iron exhibits bcc structure at room temperature. Above ${900}^{\circ }C$, it transforms to fcc structure. The ratio of density of iron at room temperature to that at ${900}^{\circ }C$ (assuming molar mass and atomic radii of iron remains constant with temperature) is __________.

Q. Iron exhibits bcc structure at room temperature. Above ${900}^{\circ }C$, it transforms to fcc structure. The ratio of density of iron at room temperature to that at ${900}^{\circ }C$ (assuming molar mass and atomic radii of iron remains constant with temperature) is:
(NEET 2018)

Q. At ${100}^{\circ }C,$ copper $\left(Cu\right)$ has fcc unit cell structure with cell edge length of $x\stackrel{\circ }{A}$ . what is the approximate density of Cu $\left(\text{in g}c{m}^{-3}\right)$ at this temperature?
[Atomic mass of $Cu$ $=63.55u]$

Q. At ${100}^{o}C$, copper $\left(Cu\right)$ has $FCC$ unit cell structure with cell edge length of $x\mathring{A}$. What is the approximate density of $Cu$ (in g.cm${}^{-3}$) at this temperature?
[Atomic mass of $Cu=63.55u$]

Q. When heated above ${916}^{\circ }C$, iron changes its crystal structure from body-centered cubic to cubic closed packed structure. Assuming that the metallic radius of the atom does not change, calculate the ratio of the density of the bcc crystal to that of the ccp crystal.