Question

The meterial of a wire has density of 1.4 g/c c. If it is not wetted by a liquid of surface tension 44 dyne / cm., find the maximum radius fo the wire which can float on the surface of the liquid.

Answer 1

Correct Answer - 1.43 mm
Here `rho = 1.4 g//c c , S = 44 dyn e// cm ,r = ?` Let l be the length of the wire. As the wire floats, So, `2Sl = pi r^2 l rho g`
or `r = sqrt((2S)/(pi rho g)) = sqrt((2xx44)/((22//7)xx1.4 xx980))`
`=(1.0)/(7)cm = (10)/(7)mm = 1.43 mm`