Q1: If cohesion between the molecules of a fluid is more than adhesion between the fluid and glass, the free level of fluid in a dipped glass tube will be

ANS:C - lower than the surface of liquid

When the cohesion between the molecules of a fluid is greater than the adhesion between the fluid and the glass, the liquid tends to be more attracted to itself than to the surface of the glass. This scenario creates a concave meniscus, where the edges of the liquid curve downwards. Here's how it works:

1. Cohesion vs. Adhesion:
   • Cohesion: Cohesion refers to the attraction between molecules of the same substance. In this case, the liquid molecules are more attracted to each other.
   • Adhesion: Adhesion refers to the attraction between molecules of different substances. In this case, the liquid molecules are less attracted to the glass surface.
2. Concave Meniscus:
   • Due to greater cohesion, the liquid molecules tend to stick together more strongly than they adhere to the glass surface.
   • As a result, the liquid forms a concave shape in the glass tube. The edges of the liquid curve downwards.
3. Effect on Free Level of Fluid:
   • The concave meniscus means that the level of the liquid inside the glass tube is lower than the level of the liquid outside the tube.
   • Essentially, the liquid "pulls away" from the glass, causing the surface of the liquid inside the tube to be lower than the surface of the liquid outside the tube.