A vertical capillary with inner diameter 0.50 mm is submerged into water so that the length of its part protruding over the water surface in 25 mm. The radius of curvature of the meniscus is $\mathrm{x}\times {10}^{-4}\hspace{0.17em}\hspace{0.17em}\mathrm{m}$. Find x to nearest integer. (Surface tension of water$=73\times {10}^{-3}\mathrm{N}/\mathrm{m}$).

• A

  6

• B

  7

• C

  8

• D

  9