The density of the solution is $2.15 \ g \ mL^{-1}$,then the mass of $2.5 \ mL$ solution in correct significant figures is $........ \ g$.

What do you mean by significant figures?

Perform the following calculations for the given exponential numbers:
$(i)$ $(6.7 \times 10^4) \times (8.4 \times 10^7)$
$(ii)$ $\frac{(3.4 \times 10^{-3})}{(6.5 \times 10^{-7})}$

Consider the following:
$A) 0.0025$
$B) 500.0$
$C) 2.0034$
Number of significant figures in $A, B$ and $C$ respectively,are

Which of the following have the same number of significant figures?
$(A)$ $0.00253$
$(B)$ $1.0003$
$(C)$ $15.0$
$(D)$ $163$
Choose the correct answer from the options given below:

Fill in the blanks given below:
$(i)$ At ........ ${\,^\circ }{\text{C}}$,the values of temperature in both ${\,^\circ }{\text{C}}$ and ${\,^\circ }{\text{F}}$ are equal.
$(ii)$ The number of significant figures in $0.03$ is .....
$(iii)$ The closeness of various measurements for the same quantity is called .........
$(iv)$ The agreement of a particular value to the true value of the result is called ....