Question

If the shape of the liquid surface is curved, then

• A. the pressure on convex side is equal to atmosphereic pressure.
• B. the pressure on the convex side is equal to pressure on concave side.
• C. the pressure on the concave side is greater than that on the convex side.
• D. the pressure on the concave side is lesser than that on the convex side.

Hint:

Surface tension makes the concave side of a curved surface the high pressure side.

Answer 1

The Correct Option is C

Step 1: Think of a soap bubble:
The air inside a bubble is at a higher pressure than the air outside. The inside of the film is the concave side and the outside is the convex side.

Step 2: Generalise:
Surface tension pulls the surface towards its centre of curvature. To balance this inward pull, the pressure must be larger on the concave side, which is where the centre of curvature lies.

Step 3: Match with the options:
Only (C) says the concave side has the greater pressure. A flat surface has equal pressure on both sides, but the question has a curved surface.

Final Answer:
Option (C). \[ \boxed{P_{concave} > P_{convex} \text{ (C)}} \]