Tiêu đề 2.SURFACE TENSION_Final (15-28).pdf ✅

NISHITH Multimedia India (Pvt.) Ltd., 1 5 JEE MAINS - CW - VOL - I JEE ADVANCED - VOL - IV NISHITH Multimedia India (Pvt.) Ltd., SURFACE TENSION SURFACE TENSION LEVEL-V SINGLE ANSWER TYPE QUESTIONS 1. Find the maximum possible mass of a greased needle floating on water surface. T is the surface tension of water, l is the length of the needle A) max 2Tl m g  B) max 2 g m Tl  C) max 2Tg m l  D) max Tl m g  2. A vertical capillary with inside diameter 0.50mm is submerged into water so that the length of its part emerging outside the water surface is equal to 25 mm.Find the radius of curvature of the meniscus.Surface tension of water is 3 73 10 / N m   . A) R m  0.6 B) R mm  6 C) R mm  0.6 D) R Km  0.6 3. Expression for the height of capillary rise between two parallel plates dipping in a liquid of density  separated by a distance d. The surface tension of the liquid is T. A) 2T h dg  B) 2d h T  C) T h d   D) 2 2T h d  4. A glass capillary sealed at the upper end is of length 0.11m and internal diameter 5 2 10  m. The tube is immersed vertically into a liquid of surface tension 2 5.06 10 / . N m   To what length the capillary has to be immersed so that liquid level inside and outside the capillary becomes the same.? A) 5cm B) 3cm C) 1cm D) 7cm 5. A vertical communicating tube contains a liquid of density  .If it moves with a horizontal acceleration “a”, pressure at ‘A’ is equal to; A) 2 0 2 2T gh P al r      B) 2 0 2 2T gh al P r      C) 1 0 1 2T gh P r    D) 1 0 1 2T gh P r    6. A glass rod of diameter d = 2mm is inserted symmetrically into a glass capillary tube of radius r=2mm. Then the whole arrangement is vertically dipped into liquid having surface tension 0.072 Nm.The height to which liquid will rise on capillary is (  2 3 10 / , 1000 / Takeg m s p kg m   liq . Assume contact angle to be zero. capillary tube to be long enough) A) 1.44cm B) 6cm C) 4.86cm D) 5.26cm 7. A vertical capillary tube with inside diameter 0.50 mm is submerged into water so that the length of its part protruding over the water surface is equal to h mm  25 .The radius of curvatureof the meniscus is (surface tension T=0.073 N/m, density of water 3 3 10 / kg m ) A) 0.2 mm B) 0.4 mm C) 0.6mm D) 0.8mm
1 6 NISHITH Multimedia India (Pvt.) Ltd., JEE ADVANCED - VOL - IV NISHITH Multimedia India (Pvt.) Ltd., SURFACE TENSION 8. Surface tension of the soap water solution T is 45 mN/m . Find the capillary pressure inside a soap bubble of diameter d mm  3.0 A. 3 1.2 10  atm B. 3 0.6 10  atm C. 3 2.4 10  atm D. 3 0.3 10  atm 9. In the bottom of a vessel with mercury there is a round hole of diameter d m  70 . At what maximum thickness of the mercury Layer will the liquid still not flow out through this hole? 3    gh kg m  13600 /   (A) 11cm (B) 21 cm (C) 42cm (D) 32cm 10. An air bubble of diameter, d m  4 is located in water at a depth h m  5.0 Considering standard atmospheric prssure as 1 atm, find the pressure in the air - bubble? (A) 2.2 atm (B) 1.2 atm (C) 3.2 atm (D) 1.6 atm 11. Water rises to a height of 10 cm in a capillary tube and mercury falls to a depth of 3.42 cm in the same capillary tube. If the denisty of mercury is 13.6 g/c.c. and the angles of contact for mercury and water are 0 135 and 0 0 , respectively, the ratio of surface tension for water and mercury is (A) 1: 0.15 (B) 1:3 (C) 1: 6.5 (D) 1.5:1 12. A glass rod of radius 1 r is inserted symmetrically into a vertical capillary tube of radius 2 r such that their lower ends are at the same lebel. The arrangement is now dipped in water. The height to which water will rise into the tube will be  = surface tension of warer ,  = density of water) A.  2 1  2 r r g    B. r r g 2 1     C.  2 1  2 r r g    D.   2 2 2 1 2 r r g    13. A large number of droplets, each of radius a , Coalesce to from a bigger drop of radius b . Assume that the energy released in the process is converted into the kinetic energy of the drop. The velocity of the drop is ( =surface tension,  = density) A. 1/ 2 1 1 a b                B. 1/ 2 2 1 1 a b                C. 1/ 2 3 1 1 a b                D. 1/ 2 6 1 1 a b                14. Two glass plates are separated by water. If surface tension of water is 75 dync/cm and the area of each plate wetted by water is 2 8cm and the distance between the plates is 0.12mm , then the force applied to separate the two plates is A. 0 10 dyn B. 4 10 dyn C. 5 10 dyn D. 6 10 dyn 15. The lower end of a capillary tube is at a depth of 12 cm and water rises 3cm in it. The mouth pressure required to blow an air bubble at the lower end will be x cm of water column, where x is A. 12 B. 15 C. 3 D. 9 16. A film of soap solution is trapped between a vertical frame and a light wire ab of length 0.1m . If 2 g m s 10 / . Then the load W that should be suspended from the wire to keep it in equilibrium is W a a A. 0.2 g B. 0.3g C. 0.4 g D. 0.5g 17. The angle of contact between glass and water is 0 0 and water (surface tension 70 dyn/cm) rises in a glass capillary up to 6 cm. Another liquid of surface tension 140dyn/cm. Angle of contact 0 60 and relative density 2 will rise in the same capillary up to A. 12cm B. 24 cm C. 3cm D. 6cm 18. Work W is required to from a bubble of volume V from a given solution. What amount of work is required to be done to form a bubble of volume 2V ? A. W B. 2W C. 1/3 2 W D. 1/3 4 W
NISHITH Multimedia India (Pvt.) Ltd., 1 7 JEE MAINS - CW - VOL - I JEE ADVANCED - VOL - IV NISHITH Multimedia India (Pvt.) Ltd., SURFACE TENSION 19. Two verical parallel glass plates are particlly submerged in water. The distance between the plates is d and the length is l . Assume that the water between the plates does not reach the upper edges of the plates and that the wetting is complete. the water will rise to height (  - density of water and  = surface tension of water) A. 2 gd   B. 2 gd   C. 4 gd   D. 5 gd   20. A drop of liquid of density  is floating half - immersed in a liquid of density d . If  is the surface tension, the diameter of the drop of the liquid is: A. g d 2     B.   2 g d 2    C.   6 g d 2    D.   12 g d 2    MULTIPLE ANSWER QUESTIONS 21. Excess pressure can be (2T/R) for A. spherical drop B. spherical meniscus C. cylindrical bubble in air D. spherical bubble in water 22. If n drops of a liquid, each with surface energy E, join to from a single drop, then A. Some energy will be released in the process B. Some energy wil be released in the process C. the energy released or ansorbed wil be   2 /3 E n n  D. the energy released or absorbed will be   /3 nE 2 1   23. When a capillary tube is dipped in a liqiud, the liquid rises to a height h in the tube. the free liquid surface inside the tube is hemispherical in shape. The tube is now pushed down so that the height of the tube outside the liquid is less than h . Then A. The liquid will come out of the tube like in a small fountion B. The liquid will ooze out of the tube slowly C. The liquid will fill the tube but not cime out of its upper end D. The free liquid surface inside the tube will not be hemispherical 24. A capillary tube of radius’ r’ is lowered into water whose surface tension is ' '  and density ‘d’.The liquid rises to a height. Assume that the contact angle is Zero. Choose the correct statement(s): A) Magnitude of work done by force of surface tension is 2 4 dg  B) Magnitude of work done by force ofsurface tension is 2 2 dg  C) Potential energy acquired by the water is 2 2 dg  D) The amount of heat developed is 2 2 dg  MATRIX MATCHING TYPE This section contains 4 questions. Each question contains statements given in two column which have to be matched. Statements (A, B, C, D) in Column I have to be matched with statements (p, q, r, s) in Column II. The answers to these questions have to be appropriately bubbles as illustrated in the following example. If the correct matches are A–p, A–s, B–q, B–r, C–p, C–q and D–s, then the correctly bubbled 4 × 4 matrix should be as follows : 25. A column of alcohol is raised in a capillary tube of internal radius of r = 0.6mm. The lower meniscus of the column hangs from the bottom end of the tube. Match the height h of the alcohol column given in Column II with the radius of curvature R of the lower meniscus given in Column I. Consider that wetting is complete Surface tension of alcohol T N m  0.02 / and density of alcohol 3   790 / kg m . Column I Column II A) if R= 3r p) 8.3 mm B) if R = 2r q) 12.5 mm C) if R = 4r r) 5.5 mm D) if R = -3r s) 22.2 mm
1 8 NISHITH Multimedia India (Pvt.) Ltd., JEE ADVANCED - VOL - IV NISHITH Multimedia India (Pvt.) Ltd., SURFACE TENSION 26. Capillary rise and shape of droplets on a plate due to surface tension are shown in Column - II match the following Column - I a) Adhesive force is greater than cohesive force b) Cohesive force is greater than adhesive force c) Pressure at A > pressure at B d) Pressure at B > pressure at A Column - II p) .............................. ......... A Capillary in water B .............................. .............................. .............................. .............................. ......... ......... ......... ......... q) .............................. A Capillary in water B .............................. .............................. .............................. .............................. r) B A Mercury drop between glass plates s) Mercury drop on glass plate B A STATEMENT TYPE QUESTIONS A) Both Statement 1 and Statement 2 are true and Statement 2 is the correct explanation of Statement 1. B) Both Statement1 and Statement2 are true but Statement 2 is not the correct explanationof Statement 1. C) Statement 1 is true but Statement 2 is false. D) Statement 1 is false but Statement 2 is true. 27. Statement I: Tiny drops of liquuid resist deforming forces better than bigger drops. StatementII: Excess pressure inside a drop is directly proportional to surface tension. 28. Statement I: A needle placed carefully on the surface of water may float, whereas the ball of the same material will always sink. Statement II: The buoyancy of an object depends both on the material, shape of the object. 29. Statement I: Droplets of liquid are usually more spherical in shape than large drops of the same liquid. StatementII: Force of surface tension predominates the force of gravity in case of small drops. 30. Statement I: Spraying of water causes cooling. StatementII: For an isolated system, surface energy increase at the expence of internal energy. 31. Statement I: Finer the capillary, greater is the height to which the liquid rises in the tube. Statement II: This is in accordance with the ascent formula. 32. Statement I : A needle placed carefully on the surface of water may float, whereas the ball of the same material will always sink. Statement II: The buoyancy od ana object depends both on the meterial and shape of the object 33. Statement I: while blowing a soap bubble, to increase the size of soap babble, we have to increase the air pressurre within the soap bubble Statement II: To increase the size of soap LEVEL-V KEY SINGLE ANSWER TYPE 1) A 2) C 3) A 4) C 5) C 6) A 7) C 8). A 9) B 10). A 11) C 12) A 13) D 14) C 15) B 16) D 17) C 18 ) D 19) A 20) D MULTIPLE ANSWER TYPE 21) A,B,C,D 22) A.C 23) C.D 24) ACD MATRIX MATCHING TYPE 25) A-r; B-p; C-s; D-q 26) a p b q r s c p r s d q     ; , , ; , , ; STATEMENT TYPE 27) B 28 )C 29) A 30) A 31) A 32) C 33)D