Question

In the set-up shown in the given figure, assuming the specific weight of water as 10,000 N/$m^3$, the pressure difference between the points A and B will be

• A. 10 N/$m^2$
• B. -10 N/$m^2$
• C. 20 N/$m^2$
• D. -20 N/$m^2$

Answer 1

The correct option is B -10 N/$m^2$

The equation for pressure at B is
${\rho }_A-{\rho }_{w}gh-{\rho }_{oil}gh+2{\rho }_{w}gh={\rho }_B\therefore {\rho }_A-{\rho }_B={\rho }_{oil}gh-{\rho }_{w}gh=(0.98-1)\times 10000\times 0.05=-10N/m^2$