Question

Assertion: A large force is required to draw apart normally two glass plates enclosing a thin water film.
Reason: Water works as glue and sticks two glass plates

• A. If both Assmertion and Reason are true and the Reason is the correct explanation of the Assertion
• B. If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.
• C. If Assertion is true statement but Reason is false.
• D. If both Assertion and Reason are false statements.

Answer 1

The correct option is C If Assertion is true statement but Reason is false.

In this case, atmospheric pressure does not comes into it because it acts in all direction. The force which is effective in case of water between two pieces of glass is adhesive force. As, adhesive forces are considered that between two different bodies; cohesive forces are internal forces of a body, resulting from attraction between the molecules of it.The attractive force between water and glass (the glass contain silicium atoms,negatively charged and water is a polar molecule so that the positive side of water is attached and causes part of the bound) keep them firmly together. Due to the big surface of the glass slide, the resultant force is also big. So we have to apply a large force in order to separate two glass plates enclosed with water film.