JEE Main | 2014Momentum and CollisionVery Hard
Question
On heating water, bubbles being formed at the bottom of the vessel detatch and rise. Take the bubbles to be spheres of radius R and making a circular contact of radius r with the bottom of the vessel. If r << R, and the surface tension of water is T, value of r just before bubbles detatch is (Density of water is ρw)


Options
A.R2
B.

C.

D.

Solution

When the bubble gets detached,
Buoyant force = force due to surface tension
∫ T × dl sin θ =
π R3 ρwg⇒ T × 2πr ×
π R3 ρwg⇒ r2 =

⇒ r = R2

Create a free account to view solution
View Solution FreeMore Momentum and Collision Questions
Two masses of 1g and 4g are moving with equal kinetic energy. The ratio of the magnitude of their linear momentum is -...One end of uniform wire of length L and of weight W is attached rigidly to a point in the roof and a weight W1 is suspen...A man of 50 kg mass is standing in a gravity free space at a height of 10 m above the floor. He throiws a stone of 0.5 k...A particle of mass m moving in the x direction with speed 2υis hit by another particle of mass 2m moving in the y ...Bob $B$ of mass $m$ at rest is hanging vertically from the ceiling via a massless string of length 10 m, as shown in the...