Question

A metallic wire of density $d$ floats horizontally in water. The maximum radius of the wire such that it may not sink will be:

(Given, surface tension of water = $T$ and neglect buoyant force)

• A. $\sqrt{\frac{2T}{\pi dg}}$
• B. $\sqrt{2T\pi dg}$
• C. $\sqrt{\frac{2\pi T}{dg}}$
• D. $\sqrt{\frac{dg}{2\pi T}}$

Answer 1

The correct option is A $\sqrt{\frac{2T}{\pi dg}}$

$2Tl\cos \theta =\pi r^{2}ldg$
$\Rightarrow r=\sqrt{\frac{2T}{\pi dg}}$