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

$A$ sample was weighed using two different balances. The results were $(I)$ $3.929 \ g$ and $(II)$ $4.0 \ g$. How would the weight of the sample be reported in $g$?

Which is the heaviest among the following?

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

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

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