Exams › JEE Main › Physics
An air bubble rises through a liquid. Apart from the buoyant force, which other forces act on the bubble during its upward motion?
- Only the force of gravity.
- The force due to gravity and the force due to the pressure of the liquid.
- The force due to gravity, the force due to liquid pressure, and the viscous force of the liquid.
- The force due to gravity and the viscous force of the liquid.
Correct answer: The force due to gravity, the force due to liquid pressure, and the viscous force of the liquid.
Solution
Buoyancy itself comes from the pressure of the liquid; but apart from the (named) buoyant force, the bubble still has its own weight (gravity), and since it moves through a viscous medium it experiences a viscous drag opposing motion. The liquid pressure also acts on it. Hence gravity, liquid pressure, and viscosity all act, in addition to buoyancy.
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 →