APS XI Physics Thermal Properties of Matter Past Paper PDF

ARMY PUBLIC SCHOOL, SHANKAR VIHAR CLASS – XI, PHYSICS ASSIGNMENT – THERMAL PROPERTIES OF MATTER Multiple Choice Questions 1. The temperature of an object measured with Fahrenheit scale as 50...

ARMY PUBLIC SCHOOL, SHANKAR VIHAR CLASS – XI, PHYSICS ASSIGNMENT – THERMAL PROPERTIES OF MATTER Multiple Choice Questions 1. The temperature of an object measured with Fahrenheit scale as 50 0 F. What will be the temperature if Celsius scale is used? (a) 300C (b) 200C (c) 100C (d) 250C 2. Which one of the following is a reliable standard fixed point? (a) Boiling point of water (b) Melting point of ice (c) Tripple point of water (d) None of the above 3. Pyrex glass is suitable for making thermometers than ordinary glass, because ……. (a) It has greater coefficient of volume expansion (b) It has smaller Coefficient of volume expansion (c) Not easy to break (d) Cheaply available in market 4. Coefficient of volume expansion is …. (a) Equal to the coefficient of linear expansion (b) 2 times the coefficient of linear expansion (c) Smaller than coefficient of linear expansion (d) 3 times the coefficient of linear expansion 5. Co-efficient of volume expansion of ………..is independent of temperature (a) Gas (b) Solid (c) Liquid (d) None of the above 6. Consider four sealed bottles with tightly screwed lids made up of Aluminium, Brass, Iron and copper. The given metals can be arranged as Aluminium > Brass> Copper> Iron in terms of their co-efficient of linear expansion. If they are immersed in hot water of same temperature, which lid will get most loosened? (a) Copper (b) Brass (c) Iron (d) Aluminium 7. The SI unit of specific heat capacity is …. (a) J kg-1K -1 (b) J kg-1K -2 (c) J kg-2K -1 (d) J -1 kgK-1 8. Regelation refers to (a) Refreezing on withdrawal of pressure (b) Melting of ice by the application of pressure (c) Boiling of water (d) Change of state from Solid to vapour 9. During phase change, (a) The heat energy supplied is used to rise the temperature only (b) The heat energy supplied is used to rise the temperature and phase change (c) The heat energy supplied is used for changing the state only (d) None of the above statement is correct 10. The heat transfer from one end to other end of a metallic rod is due to the ….. (a) Radiation (b) Convection (c) Both radiation and convection (d) Conduction 11. By Wein’s displacement law, (a) λm T 2 = constant (b) λm T3 = constant (c) λm T = constant (d) λm T 4 = constant 12. A bimetallic strip is made of aluminium and steel (αAl > αsteel). On heating, the strip will (a) remain straight (b) get twisted (c) will bend with aluminium on concave side (d) will bend with steel on concave side. 13. There is a hole in the middle of a copper plate. When heating the plate, diameter of hole would (a) always increase (b) always decrease (c) remains the same (d) none of these 14. 15. 0.1 m3 of water at 80°C is mixed with 0.3 m 3 of water at 60°C. The final temperature of the mixture is (a) 65°C (b) 70°C (c) 60°C (d) 75°C 16. Two spheres A and B are made of the same material and have the same radius. Sphere A is hollow and sphere B is solid. Both the spheres are heated to the same temperature. Which of the following is correct? (a) A expands more than B. (b) A expands less than B. (c) Both the spheres expand equally. (d) Data is insufficient. 17. If wavelength at 4500 K is λm , the wavelength at 1500 K will be (a) 3 λm (b) λm /3 (c ) 9 λm (d) λm /9 18. The wavelength of radiation emitted by a body depends upon (a) the nature of the surface. (b) the area of the surface. (c) the temperature of the surface. (d) all the above factors. 19. The emissive power of a black body is proportional (T =absolute temperature) to (a) E ∝ T0 (b) E ∝ T2 (c) E ∝ T4 (d) E ∝ T3 20. If a body is heated from 27⁰ C to 92.7⁰ C, then the ratio of their energies of radiations emitted will be (a) 1 : 4 (b) 1 : 64 (c)1 : 16 (d) 1 : 25 ANSWERS OF MULTIPLE-CHOICE QUESTIONS 1. (c) 13.(a) A metal expands on heating. Therefore, 16. (c) 2. (c) diameter of the hole increases always. 17. (a) 3. (b) 14. (d) 18. (c) 4. (d) 19. (c) 5. (c) 20. (b) 6. (d) E1/ E2 = (T1/T2)4 7. (a) 8. (a) 9. (c) 10.(d) 11.(c)  12. 15. ASSERTION – REASONING QUESTIONS 1. Assertion: The density of water is maximum at 4° C. Reason: The volume of water decreases while heating from 0°C to 4°C. 2. Assertion: The coefficient of volume expansion has dimension K–1 Reason: The coefficient of volume expansion is defined the change in volume per unit volume per unit change in temperature. 3. Assertion: Thermal conductivity depends on nature of material of the wall. Reason: When temperature difference across the two sides of a wall is increased, its thermal conductivity increases. 4. Assertion: For a perfectly black body, absorption coefficient and emission coefficient is one. Reason: Perfect absorbers are perfect emitters. 5. Assertion: It is hotter over the top of a fire than at the same distance on the sides. Reason: Air surrounding the fire conducts more heat upwards. 6. Assertion: Liquid molecules have greater potential energy at the melting point. Reason: Intermolecular spacing between the molecules increases at melting point. 7. Assertion: Water kept in an open vessel will quickly evaporate on the surface of the moon. Reason: The temperature at the surface of the moon is much higher than the boiling point of water. 8. Assertion: When hot water is poured in a beaker of thick glass, the beaker cracks. Reason: Outer surface of the beaker expands suddenly. 9. Assertion: Temperatures near the sea coast are moderate. Reason: Water has a high thermal conductivity. 10. Assertion: Woollen clothes keep the body warm in winters. Reason: Air is a bad conductor of heat. ANSWERS TO 1. (b) 9. (b) ASSERTION – REASONING QUESTIONS 2. (a) 10. (a) 3. (c) 4. (a) 5. (c) 6. (c) 7. (a) 8. (c) CASE STUDY BASED QUESTIONS (I) Case Study: Matter normally exists in three states: solid, liquid and gas. A transition from one of these states to another is called a change of state. Two common changes of states are solid to liquid and liquid to gas. These changes can occur when the exchange of heat takes place between the substance and its surroundings. When ice is heated, it starts melting without any change in temperature till the melting completes. Then temperature starts rising and it becomes steady at 100o C. The graph shows change of state from ice to vapour. Explain: (i) OA (ii) AB (iii) BC (iv) tm ANSWERS: (i) Melting of ice. Both the solid and the liquid states of the substance coexist in thermal equilibrium. (ii) The heat supplied is being utilised to change water from liquid state to vapour or gaseous state. (iii) Vaporisation. Both the liquid and the vapour states of the substance coexist in thermal equilibrium. (iv) Melting point. (II) Heat energy transfer from one system to another or from one part of a system to another part, arising due to temperature difference. There are three distinct modes of heat transfer: conduction, convection, and radiation. The conduction of heat takes place in metals, convection in fluids and there is no material medium required for radiation. Answer the following questions based on the subject discussed in the paragraph: (i) Give three factors affect the rate of flow of heat in a metal bar? (ii) If the Length of the metal bar is doubled without changing area of cross-section, the rate of heat flow will become ……… (iii) The mode of heat transfer in Sea breeze and land breeze is …………….. (iv) Which mode/modes of heat conduction is responsible for heat loss in thermos bottle? ANSWERS: (i) Length, Area of cross-section and Temperature difference of two ends. (ii) Half (iii) Convection (iv) Radiation (III) (i) Which one of the following substances has highest specific heat capacity at room temperature and atmospheric pressure? (a) Water (b) Ice (c) Aluminium (d) Mercury (ii) Heat capacity of a substance is infinite. It means (a) heat is given out. (b) heat is taken in. (c) no change in temperature whether heat is taken in or given out. (d) all of these. (iii) Water is used as a coolant because (a) it has lower density. (b) it has low specific heat. (c) it has high specific heat. (d) it is easily available. (iv) Calorie is defined as the amount of heat required to raise the temperature of 1 g of water by 1°C and it is defined under which of the following conditions? (a) From 14.5°C to 15.5°C at 760 mm of Hg. (b) From 98.5°C to 99.5°C at 760 mm of Hg. (c) From 13.5°C to 14.5°C at 76 mm of Hg. (d) From 3.5°C to 4.5°C at 76 mm of Hg. (v) Find the thermal capacity of 40 g of aluminium. (s = 0.2 cal/g K) (a) 168 J/°C (b) 672 J/°C (c) 840 J/°C (d) 33.6 J/°C ANSWERS: (i) (a) Substances Specific heat capacity Water 4186 J kg–1 K–1, Ice 2060 J kg–1 K–1 , Aluminium 900 J kg–1 K–1 , Mercury 140 J Kg–1 K–1 Water has the highest specific heat capacity. (ii) (c) Infinite thermal capacity implies that there would be practically no change in temperature whether heat is taken in or given out. (iii) (c) Owing to its high specific heat, water is used as a coolant in automobile radiators as well as a heater in hot water bags. (iv) (a) 1 calorie is the amount of heat required to raise the temperature of 1 g of water from 14.5°C to 15.5°C at 760 mm of Hg. (v) (d) Thermal capacity = ms = 40 × 0.2 = 8 cal/°C = 4.2 × 8 = 33.6 J/°C