Q 11-09-024NEETJEE MainMedium
Water (surface tension $0.07$ N m$^{-1}$, contact angle $0^\circ$) rises in a glass capillary of radius $0.5$ mm. The height of rise is ($g = 10$ m s$^{-2}$)
Answer: (B) $2.8$ cm
$h = \dfrac{2T\cos\theta}{\rho g r} = \dfrac{2 \times 0.07}{1000 \times 10 \times 5 \times 10^{-4}} = 0.028$ m $= 2.8$ cm.
Solution by Sreeraj P, M.Sc Physics