NEET-XII-Physics
14: Some Mechanical Properties of Matter
- #9The contact angle between pure water and pure silver is 90°. If a capillary tube made of silver is dipped at one end in pure water, will the water rise in the capillary?Ans : No, the water will neither rise nor fall in the silver capillary.
`` \,\mathrm{\,According\,}\,\mathrm{\,to\,}\,\mathrm{\,Jurin\,}\text{'}\,\mathrm{\,s\,}\,\mathrm{\,law\,},\,\mathrm{\,the\,}\,\mathrm{\,level\,}\,\mathrm{\,of\,}\,\mathrm{\,water\,}\,\mathrm{\,inside\,}\,\mathrm{\,a\,}\,\mathrm{\,capillary\,}\,\mathrm{\,tube\,}\,\mathrm{\,is\,}\,\mathrm{\,given\,}\,\mathrm{\,by\,}``
$$ \,\mathrm{\,h\,}=\frac{2\,\mathrm{\,Tcos\theta \,}}{\,\mathrm{\,r\rho g\,}}$$
$$ \,\mathrm{\,Here\,},\,\mathrm{\,\theta \,}={90}^{0}$$
$$ \Rightarrow \,\mathrm{\,h\,}=\frac{2\,\mathrm{\,Tcos\,}{90}^{0}}{\,\mathrm{\,r\rho g\,}}$$
`` \Rightarrow \,\mathrm{\,h\,}=0``
Thus, the water level neither rises nor falls.