Question

The surface tension of water is 72 dyne/cm. Convert it in SI unit.

Answer 1

1 dyne = 10⁻⁵ N
1 cm = 10 ⁻² m

$\therefore 72\mathrm{dyne}/\mathrm{cm}=\frac{72\times {10}^{-5}\mathrm{N}}{{10}^{-2}\mathrm{m}}=72\times {10}^{-3}\mathrm{N}/\mathrm{m}=0.072\mathrm{N}/\mathrm{m}$