Question

If the value of Avogadro number is $6.023\times {10}^{23}mo{l}^{-1}$ and the value of Boltzman constant is $1.380\times {10}^{-23}J{K}^{–}$ then the number of significant digits in the calculated value of the universal gas constant is ___

Answer 1

$R=k{N}_A$

We don't have to actually do this calculation, whatever the number is, it must have the same number of significant figures as both k and Avogadro's number. Looking at the question, both of these have 4 significant figures, so the answer must be 4 too.