Tag: intermolecular forces: cohesive and adhesive forces

Questions Related to intermolecular forces: cohesive and adhesive forces

The dimension of sphere of influence of an molecules is

intermolecular forces: cohesive and adhesive forces surface tension properties of matter physics

  1. $1 A^o$

  2. $10 A^o$

  3. $100 A^o$

  4. $0.1 A^o$

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Correct Option: A
Explanation:


The Molecular range is the radius around a molecule in a substance to which the molecule can exert attraction force on another molecule$.$  This is distance$,$
Sphere of influence is the spherical space/volume around a molecule in a substance$,$ inside which the molecule at center can exert attractive force on another molecule$.$
The molecular range is very small like $1 nanometer.$
Surface tension is the surface energy $-$ additional energy required to increase surface by a unit area$.$  This is also the tension force exerted $($along the line$)$ on the boundary of a surface per unit length$.$
Hence,
option $(A)$ is correct answer.

Ball pen and fountain pen depend respectively upon the principle of

intermolecular forces: cohesive and adhesive forces surface tension properties of matter physics

  1. Surface tension and viscosity

  2. Gravitation and surface tension

  3. Surface tension and gravity

  4. Surface tension and surface tension

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Correct Option: A

If $2$ bubble of radius $r _1$ & $r _2$ are combined then find radius of common surface.

intermolecular forces: cohesive and adhesive forces surface tension properties of matter physics

  1. $\dfrac{r _1r _2}{r _1+r _2}$

  2. $\dfrac{r _1r _2}{r _1-r _2}$

  3. $\sqrt{r _1r _2}$

  4. $\dfrac{r _1+r _2}{2}$

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Correct Option: B

A liquid is contained in a vessel. The liquid-solid adhesive force is very as compared to the liquid. The shape of the liquid surface will be

intermolecular forces: cohesive and adhesive forces surface tension properties of matter physics

  1. Horizontal

  2. Vertical

  3. Concave

  4. Convex

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Correct Option: A
Explanation:

If the liquid solid adhesive force is same as that of liquid then the surface will be horizontal at zero angle of contact.

On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because

intermolecular forces: cohesive and adhesive forces surface tension properties of matter physics

  1. mercury is a metal

  2. density of mercury is greater than that of water

  3. cohesion of mercury is greater than its adhesion with glass

  4. cohesion of water is greater than its adhesion with glass

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Correct Option: C
Explanation:

Mercury remains spherical on a glass plate due to greater cohesive force between mercury molecules than adhesive force between mercury and glass plate.

A capillary tube of radius $0.25\ mm$ is submerged vertically in water so that $25\ mm$ of its length outside water. The radius of curvature of the meniscus will be $(T = 7.5\times 10^{-3} N/m)$.

intermolecular forces: cohesive and adhesive forces surface tension properties of matter physics

  1. $0.2\ mm$

  2. $0.4\ mm$

  3. $0.6\ mm$

  4. $0.8\ mm$

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Correct Option: C
Explanation:

$h= \dfrac{2T}{dgx}$

$h= \dfrac{2\times 7.5 \times {10}^-3} {1000 \times 10 \times d}$
$h=25mm$
$d= 0.6 mm$