Reynolds number (R_N) is given by (where h = Film coefficient, $$l$$ = Linear dimension, V = Velocity of fluid, k = Thermal conductivity, t = Temperature, $$\rho $$ = Density of fluid, c_p = Specific heat at constant pressure and $$\mu $$ = Coefficient of absolute viscosity)

A. $${{\text{R}}_{\text{N}}} = \frac{{{\text{h}}l}}{{\text{k}}}$$

B. $${{\text{R}}_{\text{N}}} = \frac{{\mu {{\text{c}}_{\text{p}}}}}{{\text{k}}}$$

C. $${{\text{R}}_{\text{N}}} = \frac{{\rho {\text{V}}l}}{\mu }$$

D. $${{\text{R}}_{\text{N}}} = \frac{{{{\text{V}}^2}}}{{{\text{t}}{{\text{c}}_{\text{p}}}}}$$

Answer: Option C

Solution(By Examveda Team)

Reynolds number (R_N) is given by $${{\text{R}}_{\text{N}}} = \frac{{\rho {\text{V}}l}}{\mu }$$
Where h = Film coefficient, $$l$$ = Linear dimension, V = Velocity of fluid, k = Thermal conductivity, t = Temperature, $$\rho $$ = Density of fluid, c_p = Specific heat at constant pressure and $$\mu $$ = Coefficient of absolute viscosity