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

The number of significant figures in $2.0400$ is

Provide the full forms of the following:
$(i)$ $AZT$
$(ii)$ $CFC$
$(iii)$ $SI$

How many significant figures are present in $7.964 \times 10^{3}$?

If the diameter of a carbon atom is $0.15 \,nm$,calculate the number of carbon atoms which can be placed side by side in a straight line across the length of a scale of length $20 \,cm$.

$4 \ L \ atm$ is equal to (in $cal$)