In this problem, we are given the flow velocity \( V_0 = 1 \, \text{m/s} \), the Prandtl number \( P_r = 7.01 \), the kinematic viscosity \( \nu = 10^{-6} \, \text{m}^2/\text{s} \), and the formula for the Nusselt number \( S_{hn} \) based on the Reynolds number \( Re_x \):
\[
S_{hn} = \frac{4.91}{\sqrt{Re_x}}
\]
We can use the following relation for the Reynolds number:
\[
Re_x = \frac{V_0 \cdot x}{\nu}
\]
Where \( x \) is the characteristic length (given as \( \Delta x = 0.01 \, \text{m} \)).
Substituting the known values:
\[
Re_x = \frac{1 \cdot 0.01}{10^{-6}} = 10^4
\]
Now, substitute \( Re_x = 10^4 \) into the Nusselt number equation:
\[
S_{hn} = \frac{4.91}{\sqrt{10^4}} = \frac{4.91}{100} = 0.0491
\]
Thus, the Nusselt number \( S_{hn} \) is \( 0.0491 \).