A U tube has limbs of unequal radii. If it contains water; in which limb will the level be higher\

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Professor PC Thomas Classes · Answer

In the case of water, the level in the narrow limb will be higher because water shows a capillary rise. In the case of mercury the level in the narrow limb will be lower than the level in the other because mercury shows capillary depression. The difference in levels can be calculated using the formula $$ \mathrm{h}_{1}-\mathrm{h}_{2}=\frac{2 \mathrm{~T} \cos 	heta}{\mathrm{dg}}\left[\frac{1}{\mathrm{r}_{1}}-\frac{1}{\mathrm{r}_{2}}ight] $$ where $	heta=$ angle of contact.\