Question

Radius of a capillary is $2\ast {10}^{-3}m$. A liquid of weight $6.28\ast {10}^{-4}N$ may remain in the capillary. Then the surface tension of liquid will be:

• A. $5\ast {10}^{-3}N/m$
• B. $5\ast {10}^{-2}N/m$
• C. $5N/m$
• D. $50N/m$

Answer 1

The correct option is B $5\ast {10}^{-2}N/m$

Since, Force = $T\times 2\pi R$

So,

$6.28\times {10}^{-4}=T\times 2\pi R$

$T=\frac{6.28\times {10}^{-4}}{2\times \pi \times 2\times {10}^{-3}}$

$T=5\times {10}^{-2}N/m$