Physics · Fluid Mechanics

JEE Main 2026 — 23 January, Evening Shift — Question 34

An air bubble of volume 2.9 cm32.9 \mathrm{~cm}^{3} rises from the bottom of a swimming pool of 5 m deep. At the bottom of the pool water temperature is 17∘C17^{\circ} \mathrm{C}. The volume of the bubble when it reaches the surface, where the water temperature is 27∘C27^{\circ} \mathrm{C}, is ____\_\_\_\_ cm3\mathrm{cm}^{3}. ( g=10 m/s2\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^{2}, density of water =103 kg/m3=10^{3} \mathrm{~kg} / \mathrm{m}^{3}, and 1 atm pressure is 105 Pa10^{5} \mathrm{~Pa} )

  1. Option A:

    4.2

  2. Option B:

    2

  3. Option C:

    3

  4. Option D:

    4.5

    Correct

Answer: D

Step-by-step solution

For an air bubble rising in water, the no. of moles remain constant P1 V1 T1=P2 V2 T2\frac{\mathrm{P}_{1} \mathrm{~V}_{1}}{\mathrm{~T}_{1}}=\frac{\mathrm{P}_{2} \mathrm{~V}_{2}}{\mathrm{~T}_{2}} (Patm+ρgh)2.9 cm3290 K=(Patm)V2300\frac{\left(\mathrm{P}_{\mathrm{atm}}+\rho \mathrm{gh}\right) 2.9 \mathrm{~cm}^{3}}{290 \mathrm{~K}}=\frac{\left(\mathrm{P}_{\mathrm{atm}}\right) \mathrm{V}_{2}}{300} V2=4.5 cm3\mathrm{V}_{2}=4.5 \mathrm{~cm}^{3}

Answer key and solution verified before publishing.

Practise Fluid Mechanics

Start with this question, then two more from the same chapter — with a tutor that explains every step. Free.

Exam
JEE Main 2026
Subject
Physics
Chapter
Fluid Mechanics
Topic
Buoyancy and Archimedes' Principle
An air bubble of volume 2.9 cm 3 rises from the bottom of a swimming… | JEE Main 2026 PYQ with Solution · DhiX AI