Question

Water rises to a height of 15 mm in a capillary tube having cross-sectional area 'A'. If cross-sectional area of the tube is made `"'A'"/3` then the water will rise to a height of ______.

Options

• `5sqrt2xx10^-3  "m"`

• `20sqrt3xx10^-3  "m"`

• `20sqrt3xx10^-3  "m"`

• `15sqrt3xx10^-3  "m"`

Answer 1

Water rises to a height of 15 mm in a capillary tube having cross-sectional area 'A'. If cross-sectional area of the tube is made `"'A'"/3` then the water will rise to a height of `underline(15sqrt3xx10^-3  "m")`.

Explanation:

`h prop1/r`     since A = πr², `sqrtA prop r`

`thereforeh prop1/sqrtA`

`thereforeh_2/h_1=sqrt(A_1/A_2)=sqrt3`       `becauseA_1/A_2=3`

`thereforeh_2=sqrt3  h_1=sqrt3xx15xx10^-3  "m"`