Concepts Of Physics MCQ Edition [Volume 1]PhysicsSome Mechanical Properties of Matter
If two soap bubbles of unequal radii are connected by a tube,
Options
- Athere is no flow of air
- Bair flows from the smaller bubble to the larger bubble
- Cair flows from the larger bubble to the smaller bubble until their sizes are interchanged
- Dair flows from the larger bubble to the smaller bubble until their sizes become equal
Correct answer
B. air flows from the smaller bubble to the larger bubble
Step-by-step solution
The excess pressure inside a soap bubble of radius R is given by P = 4T R , where T is the surface tension. For a smaller bubble, the radius R is less, so the excess pressure P is greater. When two bubbles of unequal radii are connected by a tube, air flows from the region of higher pressure to the region of lower pressure. Therefore, air flows from the smaller bubble to the larger bubble. As air flows out of the smaller bubble, its radius decreases further, increasing the pressure even more, while the larger bubbl