Exams › JEE Main › Physics
A cube of edge length 'a' and density 'rho' slides down a fixed inclined plane (inclined at angle theta) at a steady velocity 'v'. Between the cube's lower face and the incline there is a thin layer of viscous liquid of thickness 't'. The coefficient of viscosity of this liquid layer is:
- 3*rho*a*g*t/(5v)
- 4*rho*a*g*t/(5v)
- rho*a*g*t/v
- none of these
Correct answer: none of these
Solution
Terminal (steady) velocity means acceleration is zero, so the component of weight down the slope is balanced by the viscous shear force on the bottom film. The answer therefore depends on the incline angle theta, which the listed simple expressions do not contain, so the general result is 'none of these' unless a specific angle is given.
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 →