Question

A liquid is contained in a vertical tube of semicircular cross-section (figure 14-Q5). The contact angle is zero. The forces of surface tension on the curved part and on the flat part are in ratio

(a) 1:1

(b) 1 : 2

(c) π : 2

(d) 2 : π.

Answer 1

The correct answer is (c)**π :**2

Explanation:

The surface tension force on the curved part F = Sπr where r is the radius of the tube and is the surface tension of the liquid.

The surface tension force on the flat part F' = S2r Hence F:F' =( Sπr):( S*2r) =π:2.

Hence the option (c) is true.