Three liquids of densities 1, 2 and 3 (with 1 > 2 > 3), having the same value of surface tension T, rise to the same height in three identical capillaries. The angles of contact 1, 2 and 3 obey
- 2 > 1 > 2 > 3 0
- 0 1 < 2 < 3 < 2
- 2 < 1 < 2 < 3 <
- > 1 > 2 > 3 > 2
Answer
(2) 0 1 < 2 < 3 < 2
Solution
Capillary rise, h = 2T r g
h, T and r are the same for all three,
1 > 2 > 3 1 > 2 > 3
1 < 2 < 3
The liquids rise in the capillaries, so each angle of contact is acute ( > 0).
0 1 < 2 < 3 < 2
Answer: (2)