27/03/2020 Density and Pressure(Senior Class Physics Study by Topics) 0Comments by Gate Academy Welcome to your Density and Pressure(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. What is the theoretical maximum height through which a pump could raise water on a day when the atmospheric pressure is 760mm/Hg. (density of mercury = 13.6g/cmÂ³)19.80cm21.00cm15.56cm10.34cm2. Mechanical pumps cannotdecrease the pressure in an enclosureincrease the atmospheric pressurecompress gases in a containermove fluids in a vertical directionmove fluids in a horizontal direction3. Which of the following cannot be correctly explained using the concept of surface tension?floating of balloon in the airformation of spherical droplets when water drips from a tapcrawling of insects on the surface of a pondformation of soap bubbles4. As a result of air at the top of a barometer, the height of the mercury column is 73.5cm when it should be 75cm, the volume of the space above the mercury is 8cmÂ³. Calculate the correct barometric height when the barometer reads 74cm and the volume of the space above the mercury is 6cm.75.1cm72cm74.5cm76cm5. Relative density of zinc, brass, copper, gold and silver are 7.1, 8.5, 8.9, 19.3 & 10.5 respectively. A metal ornament which weighs 0.425kg and can displaced 50 x 10^{-6}mÂ³ of water is made ofsilverzinccopperbrassgold6. A liquid of mass 1000kg fills a rectangular tank of length 2m. If the tank is 4m high, what is the pressure at the middle of the tank?1,000N/mÂ²Â 2,000N/mÂ²Â 1,500N/mÂ²Â 10,000N/mÂ²Â 7. The instrument used for measuring atmospheric pressure isratemeterhydrometerbarometerphotometermanometer8. 1000 identical drops of oil of density 500kg/mÂ³ have a total mass of 0.0005kg. One of the drops form a thin film of area 0.5mÂ² on water. The thickness of the film is.0.0000002m0.000000003m0.000000002m0.00000002m9. Calculate the pressure on Radeyah's thumb when she exerts a force of 20N and the top of the pin is square, the length of each side being 10mm0.2N/mmÂ²20N/mmÂ²2N/mmÂ²12N/mmÂ²0.2N/mmÂ²10. When a ship sails from salt water into fresh water, the fraxction of its volume above the water surface will?increase then decreasedecreaseremains the sameincrease11. If a plastic sphere floats in liquid (density = 1000kg/mÂ³) with 0.5 of its volume submerged and floats in oil with 0.4 of its volume submerged, the density of the oil is1200kg/mÂ³1250kg/mÂ³800kg/mÂ³2000kg/mÂ³12. A rectangular solid block has length 10cm, breadth 5cm and height 2cm. If its lies on a horizontal surface and has density 100kg/mÂ³, calculate the pressure it exerts on the surface.2N/mÂ²20N/mÂ²0.2N/mÂ²200N/mÂ²13. An object weighs 22kg in water and 30kg in air. What is the upthrust exerted by the liquid on the object? (g = 10m/sÂ²)520N220N50N80N14. The mass of a stone is 15g when completely submerged in water and 10g when completely submerged in a liquid of R.D 2.0. The mass of the stone in air is12g25g5g20g15. The rise or fall of a liquid in a narrow tube is because of thethe viscousity of the liquidthe surface tension of the liquidthe friction between the walls of the tube and the liquidthe osmotic pressure of the liquid16. When a paint brush is removed from clean water, the bristles of the brush are pulled together because oflow density of waterthe weight of the brush bristlessurface tensionthe mass of the brush bristlesthe viscousity of the surrounding17. Oil from a bottle flows out more easily after it has been warmed becauseoil molecules force one another outcohesion between the oil molecules and those of the bottle is reducedosmotic pressure of the oil is increasedmolecules are given potential energy during warmingfriction between the oil layer is reduced18. A hose ejects water at a speed of 15cm/s through a hole of area 75cmÂ². If the water strikes a wall normally, calculate the force on the wall. (Assuming that the velocity of water after striking the wall is zero and density of water = 1000kg/mÂ³).0.338N0.169N0.676N0.507N19. The density of 400cmÂ³ of oil was 0.9g/cmÂ³ before frying. If the density of the oil was 0.6g/cmÂ³ after frying, assuming no loss of oil due to spilling, its new volume was240cmÂ³800cmÂ³450cmÂ³600cmÂ³360cmÂ³20. A spherical metal ball falling through a viscous liquid is acted upon by theÂ I. weight of the ballII. viscous force of the liquid on the ballIII. upthrust of the liquid on the ballI & III onlyI & II onlyII & III onlyI, II & III21. A mercury barometer, with a tube of uniform diameter and length of 850mm above the mercury level in the reservoir, reads 750mm on a day when the atmospheric pressure is 760mmHg. What will be the atmospheric pressure on a day when it reads 730mm.738.3mm130mm765.8mm100mm22. If a spherical metal bob of radius 3cm is fully immersed in a cylinder containing water and the water level rises by 1cm. What is the radius of the cylinder?3cm12cm1cm6cm23. An object of volume 1mÂ³ and mass 2kg is totally immersed in a fluid of density 1kg/mÂ³. Calculate its apparent weight20N1N2N10N24. A spiral spring, loaded with a piece of metal, extends by 10.5cm in air. When the metal is fully submerged in water, the spring extends by 6.8cm. Calculate the relative density of the metal. (Assume Hooke's law is obeyed)10.53.8417.33.725. A piece of wire gauze can be made to lie on water becausethe wire gauze is less dense than waterthe water molecules repel the wire gauze upwardof the cohesive forces between the water and the wire gauze moleculesthe water surface has the effect of an elastic thin skin26 out of 25Time is Up!