Question

If ‘M’ is the mass of water that rises in a capillary tube of radius ‘r’, then the mass of water which will rise in a capillary tube of radius ‘2r’ is ______.

Options

• M

• `M/2`

• 4M

• 2M

Answer 1

If ‘M’ is the mass of water that rises in a capillary tube of radius ‘r’, then the mass of water which will rise in a capillary tube of radius ‘2r’ is 2M.

Explanation:

We have, h = `(2Tcostheta)/(rrhog)`

Mass of the water in the capillary.

m = `rhoV`

`= rho xx pir^2h`

`= rho xx pir^2 xx (2Tcostheta)/(rrhog)` 

⇒ m α r

∴ `m_1/m_2 = r/(2r)` or m₂ = 2m₁

= 2m