Question

According to Bernoulli's equation
$\frac{P}{\rho g}+h+\frac{1}{2} \frac{v^{2}}{g}=$ constant
The terms $A, B$ and $C$ are generally called respectively :

• A. gravitational head, pressure head and velocity head
• B. gravity, gravitational head and velocity head
• C. pressure head. gravitational head and velocity head
• D. gravity, pressure and velocity head

Answer 1

Answer: (C)

According to Bernoulli's theorem, in case of steady flow of incompressible and non-viscous liquid through a tube of non-uniform cross-section, the sum of the pressure, the potential energy per unit volume and the kinetic energy per unit volume is same at every point in the tube, i.e.,
$P+\rho g h+\frac{1}{2} \rho v^{2}=$ constant
Dividing this expression by $\rho g$, we have
$\frac{P}{\rho g}+\frac{v^{2}}{2 g}+h=$ constant
In this expression $\frac{P}{\rho g}$ is called the 'pressure head', $\frac{v^{2}}{2 g}$ the 'velocity head' and $h$ the 'gravitational head'.