Question

A 10cm long wire is placed horizontally on the surface of water and is gently pulled up with a force of $2\times {10}^{-2}$ N to keep the wire in equilibrium.The surface tension of water in N/m is:

• A. $0.002$
• B. $0.001$
• C. $0.1$
• D. $0.2$

Answer 1

The correct option is C $0.1$

$T=\frac{F}{2l}$
$T=\frac{2\times {10}^{-2}}{2\times 10\times {10}^{-2}}$
$T=\frac{1}{10}=0.1$ N