The number of significant figures in $6.02 \times 10^{23}$ is

Calculate the number of seconds in $4$ days. (in $s$)

$A$ piece of metal is $3 \, in$ long. What is its length in $cm$ (in $cm$)?

Among the following,the correct statement is

The diameter of a zinc atom is $2.6 \, \mathring{A}$. Calculate $(a)$ the radius of the zinc atom in $pm$ and $(b)$ the number of atoms present in a length of $1.6 \, cm$ if the zinc atoms are arranged side by side lengthwise.

What is $NTP$ or $STP$ and $SATP$? Mention their molar volumes.