JEE Mains · Physics · STD 11 - 9.2 surface tension
When two soap bubbles of radii \(a\) and \(b ( b > a )\) coalesce, the radius of curvature of common surface is
- A \(\frac{a b}{b-a}\)
- B \(\frac{a+b}{a b}\)
- C \(\frac{ b - a }{ ab }\)
- D \(\frac{a b}{a+b}\)
Answer & Solution
Correct Answer
(A) \(\frac{a b}{b-a}\)
Step-by-step Solution
Detailed explanation
Let say \(P_{1}\) and \(P_{2}\) are the excess pressure on the two sides of the interface then the resultant excess pressure is \(P\) \(\Rightarrow P=P_{2}-P_{1}\) \(\Rightarrow \frac{4 T}{r}=\frac{4 T}{r_{2}}-\frac{4 T}{r_{1}}\)…
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
- Mass per unit area of a circular disc of radius \(\mathrm{a}\) depends on the distance \(\mathrm{r}\) from its centre as \(\sigma(\mathrm{r})=\mathrm{A}+\mathrm{Br} .\) The moment of inertia of the disc about the the axis, perpendicular to the plane and passing through its centre isJEE Mains 2020 Hard
- Match List \(I\) with List \(II\)
Choose the correct answer from the options given belowList \(I\) List \(II\) \(A\) Spring constant \(I\) \((T ^{-1})\) \(B\) Angular speed \(II\) \((MT ^{-2})\) \(C\) Angular momentum \(III\) \((ML ^2)\) \(D\) Moment of Inertia \(IV\) \((ML ^2 T ^{-1})\) JEE Mains 2023 Medium - Water falls from a height of 200 m into a pool. Calculate the rise in temperature of the water assuming no heat dissipation from the water in the pool.
\(\left(\right.\)Take \(g=10 \mathrm{~m} / \mathrm{s}^2\), specific heat of water \(\left.=4200 \mathrm{~J} /(\mathrm{kg} \mathrm{K})\right)\)JEE Mains 2025 Medium - A wooden block floating in a bucket of water has \(\frac{4}{5}\) of its volume submerged. When certain amount of an oil is poured into the bucket, it is found that the block is just under the oil surface with half of its volume under water and half in oil. The density of oil relative to that of water isJEE 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
- Two wires \(W_1\) and \(W_2\) have the same radius \(r\) and respective densities \({\rho _1}\) and \({\rho _2}\) such that \({\rho _2} = 4{\rho _1}\). They are joined together at the point \(O\), as shown in the figure. The combination is used as a sonometer wire and kept under tension \(T\). The point \(O\) is midway between the two bridges. When a stationary waves is set up in the composite wire, the joint is found to be a node. The ratio of the number of an tin odes formed in \(W_1\) to \(W_2\) is
JEE Mains 2017 Medium
More PYQs from JEE Mains
- A cricket ball of mass \(0.15\, kg\) is thrown vertically up by a bowling machine so that it rises to a maximum height of \(20 \;m\) after leaving the machine. If the part pushing the ball applies a constant force \(F\) on the ball and moves horizontally a distance of \(0.2\, m\) while launching the ball, the value of \(F(\) in \(N)\) is \(\left(g=10\, m s^{-2}\right)\)JEE Mains 2020 Medium
- A real gas within a closed chamber at \(27^{\circ} \mathrm{C}\) undergoes the cyclic process as shown in figure. The gas obeys \(P V^3=\mathrm{RT}\) equation for the path \(A\) to \(B\). The net work done in the complete cycle is _______.(assuming \(R=8 \mathrm{~J} / \mathrm{molK}\) )JEE Mains 2024 Hard
- Let the mirror image of a circle \(c_{1}: x^{2}+y^{2}-2 x-\) \(6 y+\alpha=0\) in line \(y=x+1\) be \(c_{2}: 5 x^{2}+5 y^{2}+10 g x\) \(+10 f y +38=0\). If \(r\) is the radius of circle \(c _{2}\), then \(\alpha+6 r^{2}\) is equal to\(.....\)JEE Mains 2022 Hard
- An insulated cylinder of volume \( 60\,cm^{3} \) is filled with a gas at \( 27^{\circ}C \) and 2 atmospheric pressure. Then the gas is compressed making the final volume as \( 20\,cm^{3} \) while allowing the temperature to rise to \( 77^{\circ}C \). The final pressure is __________atmospheric pressure.JEE Mains 2026 Medium
- Let \(\vec{a}=\hat{i}+\hat{j}+\hat{k}, \vec{b}=3 \hat{i}+2 \hat{j}-\hat{k}, \vec{c}=\lambda \hat{j}+\mu \hat{k}\) and \(\hat{d}\) be a unit vector such that \(\overrightarrow{\mathrm{a}} \times \hat{\mathrm{d}}=\overrightarrow{\mathrm{b}} \times \hat{\mathrm{d}}\) and \(\overrightarrow{\mathrm{c}} \cdot \hat{\mathrm{d}}=1\), If \(\vec{c}\) is perpendicular to \(\vec{a}\), then \(|3 \lambda \hat{d}+\mu \overrightarrow{\mathrm{c}}|^2\) is equal to _______ .JEE Mains 2025 Medium
- Let \(A\) be a square matrix such that \(A A^T=I\). Then \(\frac{1}{2} A\left[\left(A+A^T\right)^2+\left(A-A^T\right)^2\right]\) is equal toJEE Mains 2024 Medium