Question 18: Properties of Matter

Question

A capillary tube of radius 0.1 mm is partly dipped in water (surface tension 70 dyn/cm and glass water contact angle ≈ 0°) with 30° inclined with the vertical. The length of water risen in the capillary is _______ cm. (Take $g = 9.8 	ext{ m/s}^2$)

Accepted Answer

$$\begin{aligned}
& \mathrm{h}=\frac{2 \mathrm{~T} \cos 	heta}{ho \mathrm{gr}}=\frac{2 	imes 70 	imes 1}{1 	imes 980 	imes 10^{-2}} \
& \mathrm{~h}=\frac{100}{7} \mathrm{~cm} \
& \sin 60^{\circ}=\frac{\mathrm{h}}{\ell} \
& \ell=\frac{\mathrm{h} 	imes 2}{\sqrt{3}} \
& \ell=\frac{100}{7} 	imes \frac{2}{\sqrt{3}} \
& =\frac{200}{7 	imes \sqrt{3}} \
& =16.49 \mathrm{~cm}
\end{aligned}$$

Answer

$\frac{82}{5}$

Answer

$\frac{68}{5}$

Answer

$\frac{57}{2}$

Answer

$\frac{71}{5}$

Properties of Matter

A capillary tube of radius 0.1 mm is partly dipped in water (surface tension 70 dyn/cm and glass water contact angle ≈ 0°) with 30° inclined with the vertical. The length of water risen in the capillary is _______ cm. (Take g = 9.8 \text{ m/s}^2)

Choose the correct answer: