Question

the surface tension acts​

Answer 1

• In bubble, the force due to excess pressure inside the bubble acts upward whereas the force due to surface tension acts downwards even though it is tangential.

• Hence the force due to excess air pressure is balanced by the force due to surface tension.

• The perpendicular force is due to difference between the air pressure inside and outside the bubble.

This difference between the air pressures depends on the surface tension.

• The air pressure inside the bubble is always greater than the air pressure outside the bubble to maintain the spherical shape.