A long glass capillary tube is dipped in water. It is known that water wets glass. The water level rises by h in the tube. The tube is now pushed down so that only length h/2 is outside the water surface. The angle of contact at the water surface at the upper end of the tube will be_____

O tan₂⁻¹
O 60∘
O 30∘
O 15∘