When a capillary tube filled with water is placed vertically, column of water of length h will be held by the upper and the lower meniscus of water as shown in figure.

If r is radius of the tube, then weight of the water in the tube.

$\mathrm{mg}={\mathrm{\pi r}}^2\mathrm{h\rho g}$

The weight of the liquid is supported by the force due to surface tension in the two menisci i.e.

$\mathrm{F}=2\mathrm{\pi rT}+2\mathrm{\pi rT}=4\mathrm{\pi rT}$

where T is surface tension of the water.

In equilibrium, $\mathrm{mg}=\mathrm{F}$

$\text{ i.e., }{\mathrm{\pi r}}^2\mathrm{h\rho g}=4\mathrm{\pi rT}$

$\mathrm{h}=\frac{4\mathrm{T}}{\mathrm{r\rho g}}=\frac{4\times 75}{0.1\times 1\times 1000}=3 \mathrm{cm}$