Question

Soapy water drips from a capillary tube. When the drop breaks away, the diameter
of its neck is D. The mass of the drop is m. Find the surface tension of soapy
water?
1)
$mg \div {\pi}^{2} d$
2)
$mg \div \pi {d}^{2}$
3)
$mg \div \pi \times d$
4)
$mg \div 2\pi \times d$
​

Answer 1

Surface Tension = Force/ Circumference

= mg/2πd