Capillarity

capillarity ( The rise or fall of fluid th rough a narrow tube is car illarity - * Due to angle of contact the surface is not flat. So there will be some excess pressure at the surface. Due to this excess pressure liq via tries to balance this ex. cess pressure by raising or falling through tube. capillary height The excess pressure is bala. nce by height of liquid CO- lumn. hig = 2T R h=2T = R ==drop Reg h= 2T coso = 90° rpg COS90=0 C h-o R B or 90-0 6 If

D ,90° coso = - -ve h = - ve (fall)