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. Which of the following explains the concave meniscus of water in glass tube?the adhesion between water and glass is greater than the cohesion between water moleculesthe molecules of water near the glass are moving faster than the molecules in the other partsthe molecules of water at the water-air boundary are often attracted to the center of the tubethe cohesion between water molecules is greater than the adhesion between glass and waterthe weight of the water pulls the central part of the surface down2. Which of the following statements is/are correct about the common hydrometer?I. it has a long narrow stemII. the R.D values marked on the stem increases down the stemIII. it has a wide bulbIV. the bulb is loaded to make the hydrometer float verticallyI, II & III onlyII onlyI, II, III & IVI, III & IV onlyII & IV only3. A ship floating in clear water of density 1000kg/m³ moves to sea water of density 1050kg/m³ where it floats again. The upthrust on the ship then?increases by 0.05 timesstays constantdecreasesincreasesdecreases by 0.05 times4. 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 10-6m³ of water is made ofzincbrassgoldcoppersilver5. Which of the following cannot be correctly explained using the concept of surface tension?formation of spherical droplets when water drips from a tapfloating of balloon in the airformation of soap bubblescrawling of insects on the surface of a pond6. The rise or fall of a liquid in a narrow tube is because of thethe surface tension of the liquidthe viscousity of the liquidthe osmotic pressure of the liquidthe friction between the walls of the tube and the liquid7. A spherical metal ball falling through a viscous liquid is acted upon by the I. weight of the ballII. viscous force of the liquid on the ballIII. upthrust of the liquid on the ballI & III onlyI & II onlyI, II & IIIII & III only8. 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 is5g12g25g20g9. What volume of alcohol with a density of 8.4 x 10²kg/m³ would have the same mass as 4.2m³ of petrol whose density is 7.2 x 10²kg/m³?5.0m³4.9m³5.8m³3.6m³1.4m³10. The diagram is of a faultless simple mercury barometer. Which of the following is NOT correct?a vacuum exists above the mercury in the tubeif the tube is tilted, the vertical height of the mercury column will changeas the barometer is taken up a mountain, h, decreasesthe height of the column will not be the same if another liquid is used instead of mercurythe atmospheric pressure supports a column of mercury, h11. A balloon of volume 100m³ and mass 2kg is filled with helium of density 0.18kg/m³ at ground level. The surrounding air has a density of 1.28kg/m³. Calculate the maximum mass which the balloon can lift off the ground.85kg128kg120kg108kg12. Which of the following is most viscous at room temperature?kerosenepalm oilalcoholwaterpetrol13. A weightless vessel of dimensions 4m x 3m x 2m is filled with a liquid of density 1000kg/m³ and sealed. What is the maximum pressure this container can exert on a flat surface?40,000N/m² 90,000N/m² 20,000N/m² 30,000N/m² 14. Which of these statements are true of pressure in liquid?I. pressure acts equally in all directionsII. pressure decreases with depthIII. pressure at the same level of a liquid is the sameIV. pressure is dependent on the cross-section area of the barometer tubeI & III OnlyI, II & III OnlyI, II, III & IVI, III & IV Only15. A thin hydrometer floats stationary in water at a temperature of about 20ºc. If the water is gradually cooled to 0ºc, their hydrometer will.sink gradually at first and become stationary after some timerise gradually at first and becomes stationary after some timeneither rise nor fall but remains at a constant leveloscillate gradually in a vertical plane as long as the cooling continuesrise gradually at first then begins to sink slowly16. A rectangular solid block has length 10cm, breadth 5cm and height 2cm. If its lies on a horizontal surface and has density 100kg/m³, calculate the pressure it exerts on the surface.0.2N/m²2N/m²20N/m²200N/m²17. Why does a piece of cork float on water?its specific gravity is greater than that of waterthe upthrust on it when completely immersed in water in greater than its weight in airits specific gravity is the same as that of waterthe upthrust on it when completely immersed in water is less than its weight in airthere is no upthrust on it when completely immersed in water18. A solid weighs 6.4N in air, 5.4N in water and 5.6N in kerosene. Calculate the relative density of kerosene.0.750.600.500.8019. It is observed that water will wet a clean glass because thecohesion of water to glass is stronger than the cohesion of water moleculesadhesion of water molecules is weaker than the cohesion of water to glassadhesion of water molecules is stronger than the cohesion of water moleculescohesion of water to glass is weaker than the cohesion of water molecules20. If a fluid flows out of a narrow tube at a depth h below the surface, its velocity ishρg√2ghρ2gh√2ghgh21. A pilot records the atmospheric pressure outside the plane as 63cm of Hg while a ground observer records a reading of 75cmHg for the atmospheric pressure on the ground. Assuming that the density of the atmosphere is constant, calculate the height of the plane above the ground. (Relative density of Hg = 13.0 and of the air = 0.00013).13,800m12,000m6,300m7,500m22. The forces acting on a body which is suspended freely in still air from a support arefrictional and gravitational onlyfluid thrust and tension onlyfrictional, gravitational and tension onlygravitational and tension onlygravitational, tension and fluid thrust only23. What is the total pressure in cmHg at a point 15m below the surface of a fresh water reservoir. Atmospheric pressure, 76cmHg, density of mercury is 13.6g/cm³1.86cm1860cm18.6cm186cm24. A steady flow of water passes along a horizontal tube from a wide section X to the narrower section Y. Manometers are placed at P & Q as shown below. Which of the statements is correct?pressure at X is less than at Ykinetic energy of water at X = kinetic energy at Ythe manometer at P shows greater pressure than at Ythe manometer at P shows lower pressure that an Qwater velocity at X is greater than at Y25. In the diagram below, if the atmospheric pressure is 760mm, the pressure in the chamber G is690mm830mm660mm860mm26 out of 25Time is Up!
