Class 11 Important questions form Heat and Thermodynamics
2. What do you understand by the term temperature and heat?
3. What is the importance of gas thermometer?
4. Write short note on absolute temperature?
5. What is calorimetry?
6. Why does soda water bottle sometimes break in summer?
7. Explain why a beaker filled with water at 40C overflows of the temperature is decreased and increased.
8. What is the effect of temperature in density of liquid?
9. Two identical rectangular strips of copper and steel are riveted to form a bimetallic strip. What will happen on heating?
10. Why spark is produced when two stones are stricken against one another?
11. Why does food cooks faster in pressure cooker than in open vessel?
12. Why there is apparent expansion of liquid?
13. Why are small spaces left between successive rails in railway track?
14. Fishes stay alive in frozen pond in winter. Explain
15. Why does a thick glass tumbler crack when boiling water is poured on it?
16. Does coefficient of linear expansion depend on length? Justify your answer.
17. Two metallic rods of the same material but of different length are heated. Smaller rod has circular area of cross-section but larger rod has rectangular cross-section. Will their expansivity be the same or different? Give justification of your answer
18. What do you mean by differential expansion? Under what conditions its value is zero?
19. Milk boils faster than water, why?
20. What do you mean by specific heat capacity of alcohol is 2400J kg-1 0C-1?
21. Groundnuts are fried along with sand why?
22. During high fever a wet cloth is kept in the forehead of a person, why?
23. Why you get severe burn from steam at 1000C than form water at 1000C?
24. Calorimeter is made of metal but not of glass, why?
25. Water remains cool in earthen pot, why?
26. Water is not good calorimetric substance, why?
27. Why are telephone wires taut in winter and slacked in summer?
28. Explain the method of mixture for finding specific heat capacity of solid.
29. The volume of a metal sphere increases by 1.4% when it is heated from 300C to 2400C. determine coefficient of superficial expansion and coefficient of cubical expansion of metal. [Ans 4.444x10-5/0C]
30. Derive the relation between α, β and γ, where symbols have their usual meanings? 31. The length of metal rod is 150cm at 150C. Find its length when it is heated to 1500C? [α steel=2.2 x10 -5 /0C] [Ans 150.4cm]
32. The difference between the lengths of a steel rod and a brass rod is 0.6m at all temperatures. What are their lengths at 00C if α for brass is 1.8x 10-5/0C and α for steel is 1.2 x 10-5 /0C? [Ana 1.2 m and 1.8m]
33. The surface area of the metal plate is 2.4x 10-2 m2 at 200C. When the plate is heated to 1850C, its area increases by 0.8 cm2. Find the coefficient areal expansion of metal. [Ans 2.020 x 10-5 /0C]
34. The length of the rail on a railway line is 25m at 100C. During summer, maximum temperature attained in the region is 500C. Find the minimum gap between the rails. [α=1.01 x10-5 /0C] [Ans 1.2cm]
35. A hole is drilled in a copper sheet. The diameter of the hole is 4.24cm at 270C. What is the change in the diameter of the hole when the sheet is heated to 2270C? coefficient of linear expansion= 1.7x10-5/0C. [Ans 1.44x10-2cm]
36. The surface area of an iron plate is 80 cm2 at 200C. Find its surface area at 1200C. α of iron= 1.25x 10-5/0C [Ans80.2cm2]
37. A liquid occupies a volume of 2x10-4m3 at 00C. Calculate the increase in its volume of it is heated to 800C. γ of liquid is 4x10-4 K-1 [Ans 6.4x10-6m3]
38. On heating a glass block of 10,000 cm3 from 250C to 400C, its volume increases by 4cm3. Calculate coefficient if linear expansion of glass. [Ans 8.89x10-6/0C]
39. How much should be the temperature of the brass rod be increased so as to increase is length by 1%. The linear expansion of brass is 2x10-5/0C.
40. A glass flask whose volume is exactly 1000 cm3 at 00C is filled full of mercury at this temperature. When flask and mercury are heated to 1000C, 15.2cm3 of mercury overflows. If the cubical expansion of mercury is 0.000182 0C-1, find the linear expansion of the glass. [ Ans 1.0x10-5 0C-1]
41. A brass pendulum clock keeps correct time at 150C. How many seconds per day it will lose or gain at 00C? α for brass = 2x 10-5K-1 [Ans 12.96 sec]
42. Express 980F into kelvin scale.
43. Describe how the cubical expansivity of a liquid can be determined by the use of balanced column.
44. A ball of copper weighing 400 gram is transferred from a furnace to a copper calorimeter of mass 300 gram and containing 1kg of water at 200C.The temperature of water rises to 500C. What is the original temperature of the ball? Sp heat of copper= 400J/kg0C [Ans 860 0C]
45. An aluminum rod when measured with a steel scale, both being at 250C appears to be 1m long. If the scale is correct at 00C, what will be the length of the rod at 00C? linear expansion od aluminum = 26x10-6 K-1 and of steel= 12x10-6 K-1 [Ans 0.9996m]
46. The density of silver at 00C is 10310 kgm-3 and the coefficient of linear expansion is 0.000019/0C. calculate its density? [Ans 10251.566kg/m3]
47. A glass flask of volume 500cm3 is just filled with mercury at 00C. How much mercury overflows when the temperature of the system is raised to 800C. [Ans 0.24cm3] cubical expansion of glass =1.2 x10-5 /0C and of mercury = 1.8x 10-5/0C.
48. Using the following data determine the temperature at which wood will just sink in the benzene.
Density of benzene at 200C =9.0x102 Kg m-3 , Density of wood at 00C =8.8x102 kg/m3 cubical expansion of benzene= 1.2x 10 -3K-1 cubical expansion of wood=1.5x 10-4 K-1 [Ans 21.7 0C]
49. Two ends of a steel wire of length of 8m and 2mm radius are fixed to two rigid supports. Calculate the increase in tension in the wire when temperature falls by 100C. [Ans 75.36N] linear expansion of steel=12x10-6 K-1. And Y=2x1011Nm-2
50. Show the relationship between real and apparent expansion of water.
51. What is the anomalous expansion of water. Explain its advantages.
