1. Predict what would have happens if there was no current electricity?
2. Imagine, what happens if electron transfer is not possible in between of atoms.
3. What are the precautions we have to take while performing Experiment in finding the refractive index of prism?
4. Explain Paulis exclusion principle by constructing a table for Lithium element.
5. Explain the role of pH in our digestive system.
6. What happens to the image distance in the eye when we increase the distance of an object from the eye?
7. Write an Experiment to find the change of color in the reaction of an acid with a base (Neutralization) reaction.
8. What are the uses of Bleaching powder?
9. Ravi wants to make a lens. Which formula has he to follow? Write the formula and explain the terms in it.
10. What value of pH in the mouth leads to tooth decay? Why?
11. The atomic number of an element is 35. Where would you expect the position of this element in the Periodic table? Why?
12. Why are vegetable oils healthy as compared to vegetable ghee?
13. Represent the formation of oxygen molecule from oxygen atoms using Lewis notation.
14. Explain the importance of ciliary muscles in the eye.
15. Anand appreciated the law behind the making of ‘generator’. Name the law and state it.
16. Why Dobereiner, Newlands and Mendeleev were not 100% successful in their classification of Elements? Why the modern table is relatively a better classification? Predict the reason.
17. How could we use the Principle of electromagnetic induction in the case of using ATM card when its magnetic strip is swiped through a scanner?
18. Potassium, Sodium, Magnesium are high reactive metals and occur as chlorides in nature. Suggest and explain the suitable method for the extraction of the above metals from their ores.
19. Draw the electronic dot structure of ethane molecule.
20. Explain with the help of a chemical equation, how an addition reaction is used in vegetable ghee industry.
21. Why Mendeleev had to leave certain gaps in his periodic table?
22. A prism of angle A = 60°produces an angle of minimum deviation D = 30°. Find the refractive index of the material of the prism.
23. Why does the sky appear white some times?
24. Write two uses of fiber optics in daily life.
25. Least distance of distinct vision of a person is observed as 35 cm. What lens is useful for him to see his surroundings clearly? Why?
26. Draw the structure of the methane molecule. Write its bond angle.
27. What are hydrophilic and hydrophobic parts in soaps?
28. Which method do you suggest for extraction of high reactivity metals? Why?
29. How can we test the pH value of the soil?
30. What is the focal length of double convex lens kept in air with two spherical surfaces of radii R1= 30 cm and R2= 60 cm? (Refractive index of the material of the lens n = 1.5)
31. Does eye lens form a real image or virtual image? Explain it.
32. A concave mirror produces 2 times magnified real image of an object placed at 20 cm in front of it. Where is the image located?
33. Substance 'X' turns blue litmus into red. Substance 'Y' turns red litmus into blue. If the reaction takes place between X and Y, guess what are the substances to be formed? Give reason.
34. In an experiment mixing of Sodium sulphate solution to Barium chloride solution, which precipitate is formed and write chemical equation for it.
35. For the formation a virtual image in a concave mirror, where should we place the object? Draw a ray diagram to show this.
36. Doctor advised to use 2D lens. What is its focal length?
37. The gas 'X' which is obtained at the anode during the electrolysis of Sodium chloride solution, produces a compound 'Y' on reacting with dry Calcium hydroxide. The compound 'Y' is used for disinfecting drinking water to make it free of germs. Name X, Y and write the chemical equation for the reaction between them.
38. Draw a neat diagram of AC generator Name the parts.
39. Suggest an experiment to produce a rainbow in your class room and explain the procedure.
40. Draw a figure showing sub-energy levels of fourth energy level (n = 4) of Somerfield’s model and state the values of 'l' and 'n'.
41. In house hold circuits, why do we use fuses? What is the use of fuses?
42. Can a convex mirror burn a paper? Imagine why it happens?
43. Explain an activity showing the formation of precipitate in chemical reactions
44. Write the uses of nanotubes.
45. Write the difference between ionic bond and covalent bond.
46. Predict what happens if the fuse is not used in house hold electric circuits.
47. What happens if a magnetic field does not form in current carrying conductor?
48. Draw the shapes of s and p orbitals.
49. What are the uses of Plaster of Paris?
50. Predict what happens in the field of domestic use of metals if alloys were not discovered.
51. Compare the real and virtual images.
52. What are the consequences occur when the spherical mirrors were not known to human beings?
53. Sigma (σ) bond is stronger than pi (π) bond. Predict the reasons
54. Draw a ray diagram shows a point sized image with convex lens.
55. What are the uses of Washing Soda?
56. Imagine what happens if chemical bond does not form?
57. Think that lenses are not discovered. Imagine the consequences that are faced by a human suffering from eye defects.
58. What is the mirror used in car head light? Where are the bulbs kept in car head light?
59. During rainy season the power supply to our home from the electric pole will be interrupted. Why? How do you restore the current?
60. Fresh milk has a pH of 6. What happens to pH if it turns in to curd? Give reason.
61. Predict the reasons for low melting point for covalent compounds when com-pared with ionic compounds.
62. The atomic numbers of the three elements x, y and z are 2, 6 and 10 respectively.
a. Which two elements belong to the same group?
b. Which two elements belong to the same period? Give reasons for your choice.
63. Guess why sigma bond is stronger than pie bond?
64. Draw the formation of N2molecule by valence bond theory
65. Write the various uses of optical fibers in our daily life?
66. State two important uses of plaster of Paris? Write an equation of show the reaction between plaster of Paris and water?
67. A car head light uses 40 W when it releases lesser light and uses 50 W when it releases more light. In which case the resistance is more? Explain.
68. Srinivas is not able to see clearly the questions written on the blackboard placed at a distance of 5m. From him.
a. Name the defect of vision he is suffering from? Name the type of lens used to correct this defect?
b. Draw the diagram to show how this defect can be corrected?
69. Give a few applications of Faraday's law of induction in daily life.
70. How do you prevent rancidity?
71. Why does sodium atom always form a cation where as fluorine atom always form an anion.
72. The bond angle of NH3 is 107°48' according to VSEPRT. How is this acceptable?
73. A student tries to catch the coin which is inside the water, but fails to do so. Predict the reason.
74. Your friend required a resistor of resistance 10 Ω, you are having 40 Ω resistances with you.
a) How many resistors he will ask from you.
b) How will he connect the resistors?
c) Show their equivalent resistances is 10 Ω
75. If the focal length of a symmetric convergent lens is equal to the radius of curvature of its surface, then find its refractive index.
76. Draw the structure of methane molecule write its bond angle.
77. Do you agree with the statement 'All ores are minerals but all minerals need not be ores’? Why?
78. Name the four chemicals that are obtained from common salt, and write their molecular formulae.
79. Suggest reasons for the phenomenon associated with the following
i) The sky appearing blue
ii) Twinkling of stars
80. A metal ring which is slightly greater in radius than a solenoid is inserted through the solenoid and connected the two ends of the solenoid to a D.C. source. It is observed that the metal ring lights up and falls down immediately. Predict and write the reason.
81. The atomic number of an element is 35. Where would you expect the position of this element in the periodic table? Why?
82. Why do water drops (dew) form on flowers and grass during morning hours of winter?
83. Assume that an object is kept at a distance of 20 cm. in front of a Concave mirror. If its focal length is 30 cm, then what is the image distance?
84. Write two uses of fiber optics in daily life.
85. Distinguish between line spectrum and band spectrum.
86. Ranga observed that sky is beautiful with blue colour. How did he appreciate the role of molecules in the atmosphere for the blue colour?
87. Explain with the help of a chemical equation, how an addition reaction is used in vegetable ghee industry.
88. If the focal length of a symmetric convergent lens is equal to the radius of curvature of its surface, then find its refractive index.
89. How does non-metallic character change as we move?
i) Down a group and
ii) Across a period.
90. How could we use the principle of electromagnetic induction in case of using ATM card when its magnetic strip is swiped through a scanner?
91. Ravi wears a spectacle. From that his eyes observed to be bigger in size.
a) What lens is used by him?
b) What is the eye defect he is suffering from? Draw the ray diagram of the defect and explain.
92. How do you appreciate the role of octet rule in describing the properties of elements?
93. Give an example for naturally occurring endothermic reaction.
94. Draw the ray diagram of image of object which is at the centre of curvature of a concave mirror.
95. When we sit at a camp fire, objects beyond the fire seen swaying. Give the reason for it?
96. Both the precipitation and the neutralization reactions are double displacement reactions. Justify your answer with two examples.
97. Draw the ray diagram for a Concave mirror which produces a virtual image of an object on its principal axis.
98. Give the four Quantum number values of outermost electron of Oxygen atom.
99. An object is placed 20 cm from a concave mirror. If the focal length of the mirror is 30 cm, then find
a) The image distance
b) The magnification of mirror
100. How do you appreciate the coincidence of the experimental facts with the results obtained by a ray diagram in terms of behavior of images formed by lenses?
101. Raju is fond of chocolates and sweets. He found that there is a decay of his teeth. What is the reason?
102. What is neutralization reaction? Give two examples.
103. Why are we advised not to use animal fats for cooking?
104. Explain about co-ordination number. What are the co-ordination number of Na+ and Cl- ions in NaCl crystal?
105. Electronic Configuration of an element is 1s2 2s2 2p1. Write the four quantum number values for 2p1valence electron.
106. The power of lens is +2D. What kind of lens it is? And what is it focal length?