A cylindrical capillary tube of 0.2mm radius is made by joining two capillaries T1 and T2 of different materials having water contact angles of 0º and 60º, respectively. The capillary tube is dipped vertically in water in two different configurations, case I and II as shown in figure. Which of the following option(s) is(are) correct?[ surface tension of water =0.075N/m, density of water =1000kg/m3, take g=10m/s2]

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

For case II, if the capillary joint is 5cm above the water surface, the height of water column raised in the tube will be 3.75cm. (Neglect the weight of the water in the meniscus)

For case I, if the capillary joint is 5cm above the water surface, the height of water column raised in the tube will be more than 8.75cm. (Neglect the weight of the water in the meniscus)

The correction in the height of water column raised in the tube, due to weight of water contained in the meniscus, will be different for both cases.

For case I, if the joint is kept at 8cm above the water surface, the height of water column in the tube will be 7.5cm. (Neglect the weight of the water in the meniscus)

answer is A.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

h=2Tcosαρgrα1=0∘ α2=60∘h1=2×0.075cos⁡0∘(0.2)×10−3×103×10=0.075m=7.5cmh2=2×0.075×cos60º0.2×10−3×103×10=3.75cm Case 1 : If point is 5 cm above (5 cm < 7.5 cm)The contact angle or radius of curvature of meniscus will adjust itself for 5 cm height. Case 2 : 5 cm > 3.75 cm h = 3.75 cmWeight of water in meniscus will be different in two cases because angle of contact is different .

Watch 3-min video & get full concept clarity