Question

A small hollow sphere, which has a small hole in it, is immersed in water to a depth of 0.5 m before any drop penetrates into it. If surface tension for water is 0.073 N/m, the radius of the hole is :

[Assume pressure inside the sphere to be atmospheric pressure]

• A. 0.06 mm
• B. 0.03 mm
• C. 0.09 mm
• D. 0.15 mm.

Answer 1

The correct option is B 0.03 mm

Since we know that Pressure = $\frac{2T}{R}=\varrho gh$

hence, $R=\frac{2T}{\varrho gh}=\frac{2\times 0.073}{1000\times 4.8\times 0.5}$

$R=0.03mm$