The internal radius of one arm of a glass capillary U tube is r_(1) and for the second arm it is r_(2)(gt r_(1)). The tube is filled with some mercury having surface tension T and contact angle with glass equal to 90^(@) + theta. (a) It is proposed to connect one arm of the U tube to a vacuum pump- so that the mercury level in both arms can be equalized. To which arm the pump shall be connected?(b) When mercury level in both arms is same, how much below the atmospheric pressure is the pressure of air in the arm connected to the pump?

The internal radius of one arm of a glass capillary U tube is r_(1) an

1.	The internal radius of one arm of a glass capillary U tube is r_(1) and for the second arm it is r_(2)(gt r_(1)). The tube is filled with some mercury having surface tension T and contact angle with glass equal to 90^(@) + theta. (a) It is proposed to connect one arm of the U tube to a vacuum pump- so that the mercury level in both arms can be equalized. To which arm the pump shall be connected?(b) When mercury level in both arms is same, how much below the atmospheric pressure is the pressure of air in the arm connected to the pump?
Answer» <html><body><p><br/></p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :(a) To capillary of smaller radius (<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a>) `(2Tsin <a href="https://interviewquestions.tuteehub.com/tag/theta-1412757" style="font-weight:bold;" target="_blank" title="Click to know more about THETA">THETA</a>(r_(2)-r_(<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>))/(r_(1)r_(2)`</body></html>