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

If the value of Avogadro number is $6.023 \times 10^{23} \ mol^{-1}$ and the value of Boltzmann constant is $1.380 \times 10^{-23} \ J \ K^{-1}$,then the number of significant digits in the calculated value of the universal gas constant is

Match the following prefixes with their multiples:

Prefixes	Multiples
$i$. micro	$10^{6}$
$ii$. deca	$10^{9}$
$iii$. mega	$10^{-6}$
$iv$. giga	$10^{-15}$
$v$. femto	$10$

The candela is the luminous intensity,in a given direction,of a source that emits monochromatic radiation of frequency '$A$' $\times 10^{12}$ hertz and that has a radiant intensity in that direction of $\frac{1}{B}$ watt per steradian. '$A$' and '$B$' are respectively

The numbers $17.0145$ and $21.0235$ were rounded to three figures after the decimal point. The resulting numbers, respectively, are

Given $P = 0.0030 \ m$,$Q = 2.40 \ m$,$R = 3000 \ m$. The significant figures in $P, Q$,and $R$ are respectively: