Question

Water rises in a capillary upto a extension height such that upward force of surface tension balances the force of $75 \times 10^{-4} \,N$ due to weight of water. If surface tension of water is $6 \times 10^{-2} \,N / m$. The internal circumference of the capillary must be

• A. $12.5 \times 10^{-2} m$
• B. $6.5 \times 10^{-2} m$
• C. $0.50 \times 10^{-2} m$
• D. $1.25 \times 10^{-2} m$

Answer 1

Answer: (A)

$ F =T L $
$L =\frac{F}{L}=\frac{75 \times 10^{-4}}{6 \times 10^{-2}} $
$=12.5 \times 10^{-2} m $