Question

Figure shows a capillary rise $h$. If air is blown through the horizontal tube in the direction as shown then rise in capillary tube will be

• A. $=h$
• B. $>h$
• C. $<h$
• D. $zero$

Answer 1

The correct option is B $>h$

If air is blown then by using Bernoulli equation we can conclude as the air is blown the pressure over capillary will reduce

and $P_0=P+\rho gH$ , where P is the pressure in horizontal tube, now as air is blown , P will decrease H will increase because $P_o$ is constant (atmospheric pressure)