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
Evaluating Fluid Statements for Physics Exam Prep
This solution analyzes two statements related to fluid mechanics and surface tension to determine their correctness.
Statement I Analysis: Fluid Pressure Existence
- Statement I claims fluid pressure is exerted only on solid surfaces and does not exist everywhere in a still fluid.
- Fluid pressure actually exists at every point within a fluid, not just on surfaces. In a static fluid, pressure varies with depth but acts in all directions at any given point.
- Therefore, Statement I is false.
Statement II Analysis: Surface Tension Origin
- Statement II relates surface tension to the excess potential energy of molecules at the liquid surface compared to the interior.
- Molecules at the surface experience fewer intermolecular forces than those inside the liquid, leading to higher potential energy.
- This excess potential energy is the fundamental reason for the phenomenon of surface tension, causing the liquid surface to behave like a stretched membrane.
- Therefore, Statement II is true.
Conclusion
Based on the analysis, Statement I is false and Statement II is true. This matches option 4.
Similar Questions
A wire of length 10 cm and diameter 0.5 mm is used in a bulb. The temperature of the wire is 1727°C and power radiated by the wire is 94.2 W. Its emissivity is $\frac{x}{8}$ where x =……
(Given $\sigma = 6.0 \times 10^{-8}$ W m$^{-2}$ K$^{-4}$, $\pi = 3.14$ and assume that the emissivity of wire material is same at all wavelength.)
A water drop of radius $1$ cm is broken into eight equal droplets. Surface tension of water is $0.075$ N $m^{-1}$. The gain in surface energy is __________$\times10^{-7}$ J.(Take $\pi = 3.14$)
- Two water drops of radius 'r' each coalesce to form a single large drop. If 'T' is the surface tension, then the surface energy released in this process is:
A gas is kept in a container having walls which are thermally non-conducting. Initially the gas has a volume of $800 \ cm^3$ and temperature $27^{\circ}C$. The change in temperature when the gas is adiabatically compressed to $200 \ cm^3$ is:
(Take $\gamma = 1.5$; $\gamma$ is the ratio of specific heats at constant pressure and at constant volume)
- Match List - I with List - II.Choose the correct answer from the options given below :
List - I List - II (A) Heat capacity of body (I) $J kg^{-1}$ (B) Specific heat capacity of body (II) $J K^{-1}$ (C) Latent heat (III) $J kg^{-1} K^{-1}$ (D) Thermal conductivity (IV) $J m^{-1} K^{-1} s^{-1}$ - The surface tension of a soap solution is $3.5 \times 10^{-2}~\text{N/m}$. The work required to increase the radius of a soap bubble from $1~\text{cm}$ to $2~\text{cm}$ is $\alpha \times 10^{-6}~\text{J}$. The value of $\alpha$ is________.
($\pi = 22/7$) - A liquid drop of diameter $2\text{ mm}$ breaks into $512$ droplets. The change in surface energy is $\alpha \times 10^{-6}\text{ J}$. The value of $\alpha$ is ________. (Take surface tension of liquid = $0.08\text{ N/m}$)
- The surface tension of a soap bubble is $0.03\text{ N/m}$. The work done in increasing the diameter of bubble from $2\text{ cm}$ to $6\text{ cm}$ is $\alpha\pi \times 10^{-4}\text{ J}$. The value of $\alpha$ is __________. (Take $\pi = 3.14$)
The strain-stress plot for materials $A, B, C$ and $D$ is shown in the figure. Which material has the largest Young's modulus ?
- Consider a rectangular sheet of solid material of length 1 m and width 4 cm. The coefficient of linear expansion is $\alpha=3.1\times10^{-5}K^{-1}$ at room temperature and one atmospheric pressure. The mass of sheet $m=0.1$ kg and the specific heat capacity $C_v=900 J kg^{-1}K^{-1}$. If the amount of heat supplied to the material is $8.1 \times 10^2 J$ then change in area of the rectangular sheet is :
Important Questions from Physical and Thermal Properties of Bulk Matter
A wire of length 10 cm and diameter 0.5 mm is used in a bulb. The temperature of the wire is 1727°C and power radiated by the wire is 94.2 W. Its emissivity is $\frac{x}{8}$ where x =……
(Given $\sigma = 6.0 \times 10^{-8}$ W m$^{-2}$ K$^{-4}$, $\pi = 3.14$ and assume that the emissivity of wire material is same at all wavelength.)
A water drop of radius $1$ cm is broken into eight equal droplets. Surface tension of water is $0.075$ N $m^{-1}$. The gain in surface energy is __________$\times10^{-7}$ J.(Take $\pi = 3.14$)
- Two water drops of radius 'r' each coalesce to form a single large drop. If 'T' is the surface tension, then the surface energy released in this process is:
A gas is kept in a container having walls which are thermally non-conducting. Initially the gas has a volume of $800 \ cm^3$ and temperature $27^{\circ}C$. The change in temperature when the gas is adiabatically compressed to $200 \ cm^3$ is:
(Take $\gamma = 1.5$; $\gamma$ is the ratio of specific heats at constant pressure and at constant volume)
- Match List - I with List - II.Choose the correct answer from the options given below :
List - I List - II (A) Heat capacity of body (I) $J kg^{-1}$ (B) Specific heat capacity of body (II) $J K^{-1}$ (C) Latent heat (III) $J kg^{-1} K^{-1}$ (D) Thermal conductivity (IV) $J m^{-1} K^{-1} s^{-1}$
