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Question
For a surface molecule ______.
- the net force on it is zero.
- there is a net downward force.
- the potential energy is less than that of a molecule inside.
- the potential energy is more than that of a molecule inside.
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Solution
b and d
Explanation:
Consider the diagram where two molecules of a liquid are shown. One is well inside the liquid and the other is on the surface. The molecule (A) which is well inside experiences equal forces from all directions, hence net force on it will be zero.
And molecules on the liquid surface have some extra energy as it surrounded surround by only the lower half side of the liquid molecules.
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