Measure the missing wetting angle

A liquid with surface tension 0.050 N/m and density 1000 kg/m³ rises 20 mm in a narrow vertical tube of internal radius 0.25 mm. Take g = 10 m/s². The contact angle is measured through the liquid; neglect the meniscus-volume correction.

What contact angle is consistent with this rise?

Organize the givens & assumptions

S = 0.050 N/m
ρ = 1000 kg/m³
g = 10 m/s²
r = 0.25 mm
h = 20 mm

Static or initially equilibrated interfaces, constant uniform surface tension, negligible gravity-induced shape distortion where spherical or cylindrical curvature is specified, and negligible evaporation. Capillary heights use the narrow-tube model with equal gas pressures and a large reservoir.

A $90^\circ$
B $120^\circ$
C $60^\circ$
D $0^\circ$

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