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: Understanding the Concept:
Because of surface tension, a curved liquid surface acts like a stretched skin. This skin pulls on the surface and produces a pressure difference across it.

Step 2: Key Formula or Approach:
The excess pressure on the concave side of a curved surface over the convex side is
\[ \Delta P = \frac{2T}{R} \quad\text{(for a spherical surface)} \]

Step 3: Detailed Explanation:
For a drop or a bubble, the pressure inside (the concave side) is more than outside (the convex side). The same idea works for any curved liquid surface: the centre of curvature lies on the concave side, and the pressure is higher there.
So the pressure on the concave side is greater than the pressure on the convex side, which is option (C). Option (B) would hold for a flat surface, where there is no curvature and no pressure difference.
Option (D) states the reverse of the actual result. Option (A) does not apply, because the convex side has the lower pressure by an amount \(2T/R\).

Final Answer:
The pressure on the concave side is greater than on the convex side, option (C). \[ \boxed{P_{concave} > P_{convex} \text{ (C)}} \]