MCQ
By a surface of a liquid we mean.
- AA geometrical plane like $x=0$
- BAll molecules exposed to the atmosphere.
- ✓A layer of thickness of the order of $10^{-8} \mathrm{~m}$.
- DA layer of thickness of the order of $10^{-4} \mathrm{~m}$.
✓
Answer
Correct option: C.
A layer of thickness of the order of $10^{-8} \mathrm{~m}$.
The surface of a liquid refers to the layer of molecules that have higher potential energy than the bulk of the liquid. This layer is typically $10$ to $15$ times the diameter of the molecule.
Now, the size of an average molecule is around $1 \mathrm{~nm}=10^{-9} \mathrm{~m}$ so a diameter of $10$ to $15$ times would be of order, $10 \times 10^{-9}=10^{-8} \mathrm{~m}$.
Now, the size of an average molecule is around $1 \mathrm{~nm}=10^{-9} \mathrm{~m}$ so a diameter of $10$ to $15$ times would be of order, $10 \times 10^{-9}=10^{-8} \mathrm{~m}$.
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