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A certain number of spherical drops of a liquid of radius R coalesce to form a single drop of radius R and volume V. If T is the surface tension of the liquid, then - Physics

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प्रश्न

A certain number of spherical drops of a liquid of radius R coalesce to form a single drop of radius R and volume V. If T is the surface tension of the liquid, then

विकल्प

  • energy = `4 "VT" (1/"r" - 1/"R")` is released

  • energy = `3 "VT" (1/"r" + 1/"R")` is absorbed

  • energy = `3 "VT" (1/"r" - 1/"R")` is released

  • energy is neither released nor absorbed

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उत्तर

energy = `3 "VT" (1/"r" - 1/"R")` is released

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  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 7: Properties of Matter - Evaluation [पृष्ठ ९१]

APPEARS IN

सामाचीर कलवी Physics - Volume 1 and 2 [English] Class 11 TN Board
अध्याय 7 Properties of Matter
Evaluation | Q I. 12. | पृष्ठ ९१

संबंधित प्रश्न

Figure  (a) shows a thin liquid film supporting a small weight = 4.5 × 10–2 N. What is the weight supported by a film of the same liquid at the same temperature in Fig. (b) and (c)? Explain your answer physically.


The total free surface energy of a liquid drop is `pisqrt2` times the surface tension of the liquid. Calculate the diameter of the drop in S.l. unit.


Show that the surface tension of a liquid is numerically equal to the surface energy per unit
area.


State any two characteristics of the angle of contact


A 5.0 cm long straight piece of thread is kept on the surface of water. Find the force with which the surface on one side of the thread pulls it. Surface tension of water = 0.076 N m−1.


A cube of ice floats partly in water and partly in K.oil (in the following figure). Find the ratio of the volume of ice immersed in water to that in K.oil. Specific gravity of K.oil is 0.8 and that of ice is 0.9. 


How much amount of work is done in forming a soap bubble of radius r?


Surface tension is exhibited by liquids due to force of attraction between molecules of the liquid. The surface tension decreases with increase in temperature and vanishes at boiling point. Given that the latent heat of vaporisation for water Lv = 540 k cal kg–1, the mechanical equivalent of heat J = 4.2 J cal–1, density of water ρw = 103 kg l–1, Avagadro’s No NA = 6.0 × 1026 k mole–1 and the molecular weight of water MA = 18 kg for 1 k mole.

  1. Estimate the energy required for one molecule of water to evaporate.
  2. Show that the inter–molecular distance for water is `d = [M_A/N_A xx 1/ρ_w]^(1/3)` and find its value.
  3. 1 g of water in the vapor state at 1 atm occupies 1601 cm3. Estimate the intermolecular distance at boiling point, in the vapour state.
  4. During vaporisation a molecule overcomes a force F, assumed constant, to go from an inter-molecular distance d to d ′. Estimate the value of F.
  5. Calculate F/d, which is a measure of the surface tension.

When one end of the capillary is dipped in water, the height of water column is 'h'. The upward force of 105 dyne due to surface tension is balanced by the force due to the weight of water column. The inner circumference of capillary is ______.

(Surface tension of water = 7 × 10-2 N/m)


In most liquids, with the rise in temperature, the surface tension of a liquid ______.


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