A fluidis $$\left( {\frac{\mu }{\rho } = 0.01{\text{ c}}{{\text{m}}^2}/\sec } \right)$$    moving at critical flow condition (N_Re = 2100) through a pipe of dia 3 cms. Velocity of flow is __________ cm/sec.

A. Thermal conductivity B. Electrical conductivity C. Specific gravity D. Electrical resistivity

A. $$\frac{{\text{V}}}{{{{\text{V}}_{\max }}}} = {\left( {\frac{{\text{x}}}{{\text{r}}}} \right)^{\frac{1}{7}}}$$ B. $$\frac{{\text{V}}}{{{{\text{V}}_{\max }}}} = {\left( {\frac{{\text{r}}}{{\text{x}}}} \right)^{\frac{1}{7}}}$$ C. $$\frac{{\text{V}}}{{{{\text{V}}_{\max }}}} = {\left( {{\text{x}} \times {\text{r}}} \right)^{\frac{1}{7}}}$$ D. None of these

A. d B. $$\frac{1}{{\text{d}}}$$ C. $$\sigma $$ D. $$\frac{l}{\sigma }$$

A. $$\frac{{4\pi {\text{g}}}}{3}$$ B. $$\frac{{0.01\pi {\text{gH}}}}{4}$$ C. $$\frac{{0.01\pi {\text{gH}}}}{8}$$ D. $$\frac{{0.04\pi {\text{gH}}}}{3}$$