Rise of a liquid in a capillary tube is given by ,
h=2Tcosθrρg
or cosθ=hrρg/2T
where θ= angle of contact ,
r= radius of capillary tube ,
T= surface tension ,
ρ= density of liquid ,
now given that h , T and r are constants for all three liquids ,
and ρ1>ρ2>ρ3 ,
therefore cosθ1>cosθ2>cosθ3
or θ1<θ2<θ3
now as the liquid is rising in all three capillaries therefore angles of contact will be acute ,
0≤θ1<θ2<θ3<π2