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Surface tension, , 1. The excess pressure inside a soap bubble is three times than excess pressure inside a, soap bubble, then the ratio of their surface area is (a)9:1(b)1:3(c)1:9(d)3:1, , 2. The surface tension of soap solution is 0.03Nm™. The work done in blowing to form a, soap bubble of surface area 40cm’ is (a) 2.4x 10“) (b) 1.2x10°J (c) 3.6x10*) (d) 4.2x107), , 3. Aman sitting in a boat which is floating in a pond. If the man drinks some water from, the pond, the level of water in the pond (a) increases (b) decreases (c) remain, unchanged (d)increases or decreases depends upon the weight of man, , 4. When a drop of water splits up is to number of drops (a) area increases(b) volume, increases (c)energy is absorbed (d) both (a) and(c), , 5. A liquid does not wet the solid surface if the angle of contact is (a)zero (b)equal to, 45°(c)equal to 90°(d) greater than 90°, , 6. Mercury does not wet glass, this is property of liquid known as (a) adhesion (b)surface, tension (c)viscosity (d)compressibility, , 7. If Wi be the work to be done to form a bubble of volume V from a given solution. The, work required to be done to form a bubble of volume 2V is (a)427Wi(b) 427W, (c), 2¥?W, (d) 277Wi, , 8. Angle of contact of a liquid with a solid depends on (a)solid only (b)liquid only (c)both, on solid and liquid (d) orientation of the solid surface in liquid, , 9. The work done in blowing a soap bubble of surface tension 0.06Nm* from 2cm radius to, 5cm radius is (a)3.1mJ (b)1.25mJ (c) 2.51mJ (d)4.55mJ, , 10. When cooking oil is heated in a frying pan, the oil moves around in the pan easily when, it is hot. The main reason for this is that with rise in temperature, there is a decrease in, (a) density (b)surface tension (c)viscosity (d) angle of contact, , 11. Which of the following is associated with liquid only and not foe gases?(a) pressure, (b)volume (c)density (d) surface tension, , 12. The work done in increasing the size of a soap film from 10cm x 6cm to 10cm x 11cm is, 3x10“), the surface tension of the film is (a)1.5 x107Nm“(b) 3.0 x10?Nm" (c) 6.0 x10", 2Nm*? (d) 11.0 x107Nm?., , 13. Two water droplets merge with each other to form a larger droplet. In this process (a), energy is liberated (b) energy is absorbed (c) energy is neither liberated nor absorbed, (d)some mass is converted into energy, , 14, What change in surface energy will be noticed when a of radius R splits up into 1000, droplets of radius r, surface tension T.(a) 4nR?T(b) 7nR?7T (c) 16R?T (d) 36rnR7T, , 15. Eight drops of water, each of radius 2mm are falling through air at a terminal velocity of, 8cms". If they coalesce to form a single drop, then the terminal velocity of combined, drop will be (a) 32cms*, , (b)30cms(c)28cms(d)24cms”.