Question

The maximum force, in addition to the weight required to pull a wire of 5.0 cm long from the surface of water at temperature 20^oC, is 728 dynes. The surface tension of water is

• A. 7.28 N/cm
• B. 7.28 dyne/cm
• C. 72.8 dyne/cm
• D. 7.28×10² dyne/cm

Answer 1

Answer: (C)

72.8 dyne/cm

Answer 2

$T = \frac { F } { 2 l } = \frac { 728 } { 2 \times 5 }$

∴