In a closed packed array of $N$ spheres,the number of tetrahedral holes is

What is the percentage of space occupied in a $bcc$ arrangement (in $\%$)?

What type of crystal structure from the following has $52.36 \%$ packing efficiency?

With the help of a labelled diagram,show that there are $4$ octahedral voids per unit cell in a cubic close-packed $(CCP)$ structure.

Which of the following metals crystallizes in a hexagonal close-packed $(hcp)$ structure?

An ionic compound is formed between a metal $M$ and a non-metal $Y$. If $M$ occupies half the octahedral voids in the cubic close-packed arrangement formed by $Y$,the chemical formula of the ionic compound is