JEE Mains · Physics · STD 11 - Fluid mechanics
- JEE Mains 2019
- Hard
- Numerical
A load of mass \(M\,kg\) is suspended from a steel wire of length \(2\,m\) and radius \(1.0\,mm\) in Searle’s apparatus experiment. The increase in length produced in the wire is \(4.0\,mm.\) Now the load is fully immersed in a liquid of relative density \(2\). The relative density of the material of load is \(8\). The new value of increase in length of the steel wire is ........ \(mm\)
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) \(3\)
Step-by-step Solution
Detailed explanation
In first case:
\(\frac{{\frac{{mg}}{A}}}{{\left( {\frac{{\Delta {\ell _1}}}{\ell }} \right)}} = Y\,\,\,\,\, \Rightarrow \,\,\,\Delta {\ell _1} = \frac{{mg}}{{\left( {\frac{{YA}}{\ell }} \right)}}\)
In second case:
\(\frac{{\frac{{mg - B}}{A}}}{{\left( {\frac{{\Delta {\ell _1}}}{\ell }} \right)}} = Y\,\,\,\, \Rightarrow \,\,\Delta {\ell _2} = \frac{{mg - B}}{{\left( {\frac{{YA}}{\ell }} \right)}} = \frac{{\left( {\frac{{3mg}}{4}} \right)}}{{\left( {\frac{{YA}}{\ell }} \right)}}\)
\( \Rightarrow \,\,\Delta {\ell _2} = \frac{3}{4}\Delta {\ell _1} = 3\,mm\)
More questions from Physics
- In a Young's double slit experiment, the slits are separated by 0.2 mm. If the slits separation is increased to 0.4 mm , the percentage change of the fringe width is _______.JEE Mains 2025 Easy
- Two identical circular wires of radius \(20\,cm\) and carrying current \(\sqrt{2}\,A\) are placed in perpendicular planes as shown in figure. The net magnetic field at the centre of the circular wire is \(.............\times 10^{-8}\,T\). (Take \(\pi=3.14\) )
JEE Mains 2023 Medium - The electric field of an electromagnetic wave in free space is \(\overrightarrow{\mathrm{E}}=57 \cos \left[7.5 \times 10^6 \mathrm{t}-5 \times 10^{-3}(3 x+4 y)\right](4 \hat{i}-3 \hat{j}) N / C\). The associated magnetic field in Tesla is _______.JEE Mains 2025 Medium
- The difference of temperature in a material can convert heat energy into electrical energy. To harvest the heat energy, the material should have _________.JEE Mains 2025 Easy
- The given circuit works as :
JEE Mains 2026 Easy - Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason \(R\). Assertion \(A\) : If \(dQ\) and \(dW\) represent the heat supplied to the system and the work done on the system respectively. Then according to the first law of thermodynamics \(d Q=d U-d W\). Reason \(R :\) First law of thermodynamics is based on law of conservation of energy. In the light of the above statements, choose the correct answer from the option given below :JEE Mains 2023 Medium
More PYQs from JEE Mains
- A fighter plane of length \(20\, m\), wing span (distance from tip of one wing to the tip of the other wing) of \(15\,m\) and height \(5\,m\) is lying towards east over Delhi. Its speed is \(240\, ms^{-1}\) . The earth's magnetic field over Delhi is \(5 \times 10^{-5}\,T\) with the declination angle \( \sim {0^o}\) and dip of \(\theta\) such that \(\sin \,\theta = \frac{2}{3}\). If the voltage developed is \(V_B\) between the lower and upper side of the plane and \(V_W\) between the tips of the wings then \(V_B\) and \(V_W\) are close toJEE Mains 2016 Hard
- A small square loop of side \('a'\) and one turn is placed inside a larger square loop of side \({b}\) and one turn \((b \gg a)\). The two loops are coplanar with thei centres coinciding. If a current \(I\) is passed in the square loop of side \('b',\) then the coefficient of mutual inductance between the two loops isJEE Mains 2021 Hard
- Two charged particles, having same kinetic energy, are allowed to pass through a uniform magnetic field perpendicular to the direction of motion. If the ratio of radii of their circular paths is \(6: 5\) and their respective masses ratio is \(9: 4\). Then, the ratio of their charges will be.JEE Mains 2022 Medium