Q. Given below are two statements :
Statement I : Pressure of a fluid is exerted only on a solid surface in contact as the fluid-pressure does not exist everywhere in a still fluid.
Statement II : Excess potential energy of the molecules on the surface of a liquid, when compared to interior, results in surface tension.
In the light of the above statements, choose the correct answer from the options given below.
A. Statement I is false but Statement II is true
B. Statement I is true but Statement II is false
C. Both Statement I and Statement II are false
D. Both Statement I and Statement II are true
Explanation
In a still fluid, pressure exists at every point inside the fluid and acts equally in all directions. It is not limited only to solid surfaces. Hence, Statement I is incorrect.
Molecules at the surface of a liquid experience an unbalanced inward force due to fewer neighboring molecules. This causes them to possess higher potential energy than molecules inside the liquid, which leads to the phenomenon of surface tension. Hence, Statement II is correct.
Therefore, the correct option is Statement I is false but Statement II is true.