$A$ student performs a titration with different burettes and finds titre values of $25.2 \ mL$,$25.25 \ mL$ and $25.0 \ mL$. The number of significant figures in the average titre value is

Calculate the reported result and the number of significant figures for $(41.6325 - 41.612)$.

The dimensions of an aluminum block are $3.0 \, \text{inch} \times 4.0 \, \text{inch} \times 5.0 \, \text{inch}$. What is the mass of this block in grams? The density of aluminum is $2.7 \, \text{g/cm}^3$ and $1 \, \text{inch} = 2.54 \, \text{cm}$.

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

The number of significant figures in $6.0023$ are

The prefix zepto stands for