Name: Angle of Contact
Uploaded: 2019-07-19
Duration: 6 min 57 s
Description: What is the contact angle? Which factor does the contact angle depend on? Why does the contact angle for the same liquid on different surfaces differ? Let's...

Question

Explain that there is an excess pressure on the concave side relative to the convex side of a curved liquid surface.

Accepted Answer

A liquid molecule on the surface of liquid is attracted by force of cohesion in all directions and the force of surface tension acts tangentially to the liquid surface at rest. The direction of resultant force on a molecule on the surface of liquid depends upon the shape of liquid surface

If the liquid surface is curved, Damle cool oh on the liquid surface is acting upon by the forces $(~, ~)$ due to the surface tension along the tangent to the surface(above fig.) resolving these forces into horizontal and vertical components, we find that the horizontal component cancel each other whereas the vertical components add up. Thus a resultant force would be acting on the curved surface of the liquid which acts towards its centre of curvature. It means that, The resultant force is directed inwards in case of convex surface and outward in case of concave surface. for the curved surface of liquid to be in equilibrium, there must be an excess of pressure on its concave side than that of convex side, so that the forces of excess pressure may balance the resultant forces due to surface tension. Hence, for the curved surface of liquid to be in equilibrium, The pressure on concave side of liquid will be greater than the pressure on its convex side.

Explain that there is an excess pressure on the concave side relative to the convex side of a curved liquid surface.

Important Questions on Surface Tension

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