A capillary glass tube records a rise of `20cm` when dipped in water. When the area of cross-section of the tube is reduced to half of the former value, water will rise to a height of

Options

A. `10sqrt(2)cm`
B. `10cm`
C. `20cm`
D. `20sqrt(2)cm`

Answer

D

Explanation

Area is halved, means radius of tube is made `(1)/sqrt(2)` times.
`h=(2T cos theta)/(rrhog)` or `h prop (1)/(r)`
Hence, h will become `sqrt(2)` times.