JEE Mains · Physics · STD 11 - 9.1 fluid mechanics
In Millikan's oil drop experiment, what is viscous force acting on an uncharged drop of radius \(2.0 \times 10^{-5}\, {m}\) and density \(1.2 \times 10^{3} \,{kgm}^{-3}\) ? Take viscosity of liquid \(=1.8 \times 10^{-5}\, {Nsm}^{-2} .\) (Neglect buoyancy due to air).
- A \(3.8 \times 10^{-11}\, {N}\)
- B \(3.9 \times 10^{-10}\, {N}\)
- C \(1.8 \times 10^{-10} \,{N}\)
- D \(5.8 \times 10^{-10} \,{N}\)
Answer & Solution
Correct Answer
(B) \(3.9 \times 10^{-10}\, {N}\)
Step-by-step Solution
Detailed explanation
Viscous force \(=\) Weight \(=\rho \times\left(\frac{4}{3} \pi^{3}\right) \,g\) \(=3.9 \times 10^{-10}\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- A thermometer graduated according to a linear scale reads a value \(x_0\) when in contact with boiling water, and \(x_0/3\) when in contact with ice. What is the temperature of an object in \({}^oC\), if this thermometer in the contact with the object reads \(x_0/2\) ?JEE Mains 2019 Hard
- The velocity of a particle is given as \(\vec{v} = -x\hat{i} + 2y\hat{j} - z\hat{k}\) m/s. The magnitude of acceleration at point \((1, 2, 4)\) is _______ m/s\(^2\).JEE Mains 2026 Hard
- Suppose a uniformly charged wall provides a uniform electric field of \(2 \times 10^4 \mathrm{~N} / \mathrm{C}\) normally. A charged particle of mass \(2 \mathrm{~g}\) being suspended through a silk thread of length \(20 \mathrm{~cm}\) and remain stayed at a distance of \(10 \mathrm{~cm}\) from the wall. Then the charge on the particle will be \(\frac{1}{\sqrt{\mathrm{x}}} \ \mu \mathrm{C}\) where \(\mathrm{x}=\) _______ [use \(g=10 \mathrm{~m} / \mathrm{s}^2\)]JEE Mains 2024 Hard
- In an engine the piston undergoes vertical simple harmonic motion with amplitude \(7\, cm\) . A washer rests on top of the piston and moves with it. The motor speed is slowly increased. The frequency of the piston at which the washer no longer stays in contact with the piston, is close to ...... \(Hz\)JEE Mains 2016 Medium
- The value of acceleration due to gravity at Earth’s surface is \(9.8\, m\,s^{-2}\). The altitude above its surface at which the acceleration due to gravity decreases to \(4.9\, m\,s^{-2}\), is close to: (Radius of earth \(= 6.4\times10^6\, m\))JEE Mains 2019 Medium
- An air bubble of diameter \(6\,mm\) rises steadily through a solution of density \(1750\,kg / m ^3\) at the rate of \(0.35\,cm / s\). The co-efficient of viscosity of the solution (neglect density of air) is \(..........\,Pas\) (given, \(g =10\,ms ^{-2}\))JEE Mains 2023 Medium
More PYQs from JEE Mains
- Two simple harmonic motions are represented by the equations \({x}_{1}=5 \sin \left(2 \pi {t}+\frac{\pi}{4}\right)\) and \({x}_{2}=5 \sqrt{2}(\sin 2 \pi {t}+\cos 2 \pi {t})\) The amplitude of second motion is ....... times the amplitude in first motion.JEE Mains 2021 Medium
- If \(b\) is the first term of an infinite \(G.P\) whose sum is five, then \(b\) lies in the intervalJEE Mains 2018 Hard
- The general solution of the differential equation \((y^2 -x^3) dx -xydy = 0\, (x \ne 0)\) is (where \(c\) is a constant of integration)JEE Mains 2019 Hard
- A student measures the time period of \(100\) oscillations of a simple pendulum four times. The data set is \(90\;s\) ,\(91\;s \), \(95\;s\) and \(92\;s\). If the minimum division in the measuring clock is \(1\;s\), then the reported mean time should beJEE Mains 2016 Medium
- Match List\(-I\) with List\(-II\)
Choose the correct answer from the options given belowList\(-I\) List\(-II\) \((A)\) \(AC\) generator \((I)\) Detects the presence of current in the circuit \((B)\) Galvanometer \((II)\) Converts mechanical energy into electrical energy \((C)\) Transformer \((III)\) Works on the principle of resonance in \(AC\) circuit \((D)\) Metal detector \((IV)\) Changes an alternating voltage for smaller or greater value JEE Mains 2022 Medium - An object is allowed to fall from a height \(R\) above the earth, where \(R\) is the radius of earth. Its velocity when it strikes the earth's surface, ignoring air resistance, will be :JEE Mains 2023 Medium