AP EAMCET2004PhysicsMechanical Properties of Fluids
One end of a uniform glass capillary tube of radius r=0.025 ~cm is immersed vertically in water to a depth h=1 ~cm . The excess pressure in N / m ^2 required to blow an air bubble out of the tube (Surface tension of water =7 10⁻² ~N / m Density of water =10^3 ~kg / m ^3 . Acceleration due to gravity =10 ~m / s ^2 )
Options
- A0.0048 10^5
- B0.0066 10^5
- C1.0048 10^5
- D1.0066 10^5
Correct answer
B. 0.0066 10^5
Step-by-step solution
Excess pressure p=h d g+h^ d g p=d g (h+h^ ) where h is capillary rise = 2 T r d g aligned & = 2 7 10⁻² 25 10⁻⁵ 10^3 10 & =0.056 ~m p & =10^3 10[0.056+0.01] & =0.066 10^4 & =0.0066 10^5 Nm ⁻² aligned