The number of significant figures in $50000.020 \times 10^{-3}$ 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.

In the final answer of the expression $\frac{(29.2 - 20.2)(1.79 \times 10^5)}{1.37}$,the number of significant figures is

Fill in the blanks given below:
$(i)$ The symbol for the quantity of luminous intensity is .......... and the name of its $SI$ unit is ......... .
$(ii)$ The prefixes used for $10^{-18}$ and $10^{18}$ are ............ and ........... respectively.
$(iii)$ The $SI$ unit of density is ......... .
$(iv)$ In the ........ unit of temperature,its negative value is not possible.

Dimensions of pressure are the same as that of

The density of mercury is $13.6 \, g/cm^3$. Find the mass of $1 \, L$ of mercury. (in $, g$)