Exams › JEE Main › Physics
Water (surface tension 70 dyn/cm, contact angle 0 deg) rises 6 cm in a glass capillary. In the same capillary, a different liquid of surface tension 140 dyn/cm, contact angle 60 deg, and relative density 2 will rise to a height of
- 12 cm
- 24 cm
- 3 cm
- 6 cm
Correct answer: 3 cm
Solution
Since the same capillary is used, r and g are common. The rise is proportional to T*cos(theta)/rho. Computing the ratio with the given values shows the new liquid rises to half the water height, i.e., 3 cm.
Related JEE Main Physics questions
- A body is in motion inside a liquid, and the viscous resistive force on it is directly proportional to its speed. What are the dimensions of the proportionality constant?
- A capillary tube has its inner surface lined with wax and is then placed in water. Relative to a clean, unwaxed capillary, how do the contact angle (θ) and the height (h) to which water rises change?
- A charged, isolated spherical soap bubble of radius r has internal pressure equal to atmospheric pressure. If the charge on the bubble is given by Xπ√(2Tε), what is the value of X?
- Two capillary tubes, one of length L and radius R and the other of length 2L and radius 2R, are joined one after the other in series. If the flow rate through a single capillary is X = πPR⁴ / 8ηL, then the combined flow rate through the series arrangement is:
- A liquid will fail to wet the surface of a solid when the angle of contact is
- A gold sphere of a given size falls through a viscous liquid and attains a terminal speed of 0.2 m/s. If the gold has density 19.5 kg/m³ and the liquid has density 1.5 kg/m³, what terminal speed will a silver sphere of the same size have in the same liquid, given that silver has density 10.5 kg/m³?
⚔️ Practice JEE Main Physics free + battle 1v1 →