#### Important Questions

8th Standard EM

Reg.No. :
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Science

Time : 01:00:00 Hrs
Total Marks : 60

Part - A

50 x 1 = 50
1. Luminous intensity is the intensity of

(a)

Laser light

(b)

UV light

(c)

visible light

(d)

IR light

2. Quantities other than base quantities are called as

(a)

supplementary quantities

(b)

derived quantities

(c)

professional quantities

(d)

energy quantities

3. Normal temperature of the human body is between

(a)

98.4°Fand 99.6°F

(b)

98.40Fand 98.60F

(c)

97.4°Fand 98.6°F

(d)

97.6°Fand 99.60F

4. _______ can be used as memory or storage element in the computers.

(a)

Condutors

(b)

Insulators

(c)

Supercondutors

(d)

Semiconductors

5. Electric current (I) = ____________

(a)

Qt

(b)

t/Q

(c)

Q/t

(d)

Q/t2

6. Pressure exerted by a liquid is increased by

(a)

the density of the liquid

(b)

the height of the liquid column

(c)

Both (a) & (b)

(d)

None of the above

7. Pascal’s law is used in

(a)

hydraulic lift

(b)

brake system

(c)

pressing heavy bundles

(d)

All the above

8. _______is the force acting perpendicularly on any given surface area of a body

(a)

Pressure

(b)

Thrust

(c)

Density

(d)

Volume

9. Even if we tilt the barometric tube at various angles, the level of mercury will______

(a)

Not vary

(b)

increases

(c)

decreases

(d)

charge

10. The unit for surface tension is _________

(a)

Nm

(b)

N-1m

(c)

N-1m-1

(d)

Nm-1

11. The spherical mirror with a reflecting surface curved inward is called

(a)

convex mirror

(b)

concave mirror

(c)

curved mirror

(d)

None of the above

12. The distance from the pole to the focus is called

(a)

Pole length

(b)

focal length

(c)

principal axis

(d)

None of the above

13. __________ form the perfect image of an object

(a)

Spherical mirrors

(b)

Parabolic mirrors

(c)

Plane mirrors

(d)

Cylindrical mirrors

14. An imaginary line perpendicular to the reflecting surface is called

(a)

imaginary line

(b)

curved line

(c)

Perpendicular line

(d)

normal

15. When the angle of inclination decreases the number of images formed _________

(a)

increase

(b)

decreases

(c)

remain same

(d)

none of the above

16. Which one of the element name not derived from planet?

(a)

Plutonium

(b)

Neptunium

(c)

Uranium

(d)

Mercury

17. Which one of metal possess low tensile strength?

(a)

Silver

(b)

Copper

(c)

Zinc

(d)

Aluminium

18. The smallest particle of an element is__________

(a)

atom

(b)

molecule

(c)

Compound

(d)

element

19. Compound obtained from living sources such as plants and animals are called

(a)

In Organic Compounds

(b)

Organic Compounds

(c)

Synthetic Compounds

(d)

Artificial Compounds

20. The compound used for the sterilisation of drinking water is________

(a)

baking soda

(b)

washing soda

(c)

quick lime

(d)

bleaching powder.

21. The burning of matchstick is an example for chemical reaction based on______

(a)

Contact

(b)

electricity

(c)

light

(d)

catalyst

22. ______ metal undergoes rusting.

(a)

tin

(b)

sodium

(c)

copper

(d)

iron

23. Rusting of iron is a _________ change.

(a)

physical

(b)

chemical

(c)

physical and chemical

(d)

neutral

24. The chemical reactions carried out by the passage of electricity is called.

(a)

Rusting

(b)

Thermolysis

(c)

Electrolysis

(d)

Photolysis

25. Enzymes and yeasts are called

(a)

catalysts

(b)

bio catalysts

(c)

chemical catalysts

(d)

physical catalysts

26. Micro organisms are measured in ______.

(a)

cm

(b)

mm

(c)

micron

(d)

meter

27. ______ is a prokaryotic micro organisms.

(a)

Virus

(b)

algae

(c)

fungi

(d)

bacteria

28. _________is a ball-shaped bacteria.

(a)

Bacilli

(b)

Spinilla

(c)

Cocci

(d)

Vibrio

29. __________is an example for Lophotrichous

(a)

vibrio

(b)

Pseudomonas

(c)

Rhodospirillum

(d)

Corny bacterium

30. Plasmodium belongs to _________ type of protozoan.

(a)

Ciliates

(b)

Flagellate

(c)

Pseudopods

(d)

sporozoans

31. _________ is an example for colonial form of algae.

(a)

Oscillatoria

(b)

Nostac

(c)

Volvox

(d)

Chlorella

32. The well-developed sporophytic plant body is seen in

(a)

Bryophytes

(b)

Pteridophytes

(c)

Gymnosperms

(d)

Angiosperms

33. ______ is the earliest system of classification in plants.

(a)

Natural system of classification

(b)

Artificial system of classification

(c)

Phylogenetic system of classification

(d)

Modern system of classification

34. ______ is used as a food for domestic animals

(a)

Gelidium

(b)

Ascophyllum

(c)

Laminaria & Ascophyllum

35. Cercospora personata causes _________

(a)

Wilt disease

(b)

Red rot of sugar cane

(c)

Blast disease

(d)

Tikka disease

36. ______________ cells are specialised cells that can be transformed into any kind of cells.

(a)

Nerve

(b)

Stem

(c)

Heart

(d)

Bone

37. Osmosis is the movement of water molecules from a ___________.

(a)

Higher concentration to a region of lower concentration.

(b)

Lower concentration to a region of higher concentration.

(c)

Both of these

(d)

None of these

38. _________make up organs

(a)

Cells

(b)

Tissues

(c)

Organ system

(d)

None of the above

39. _______tissues for conduction of nerve impalses

(a)

Epithelial

(b)

Muscular

(c)

Nervous

(d)

Supporting

40. Which one of the following is an input device?

(a)

Speaker

(b)

Keyboard

(c)

Monitor

(d)

Printer

41. Pen drive is _____device.

(a)

Output

(b)

Input

(c)

Storage

(d)

Connecting cable

42. When was the first computer introduced?

(a)

1980

(b)

1947

(c)

1946

(d)

1985

43. Which of the following component are used in fourth generation?

(a)

Vaccum tubes

(b)

Microprocessor

(c)

Integrated circuits

(d)

Transistor

44. Which of the following substances will absorb more heat energy?

(a)

Solid

(b)

Liquid

(c)

Gas

(d)

All the above

45. Which of the following a simple circuit must have?

(a)

(b)

(c)

Energy Source, Wire, Switch

(d)

Battery, Wire, Switch

46. Which of the following is known as azote?

(a)

Oxygen

(b)

Nitrogen

(c)

Sulpher

(d)

Carbon dioxide

47. In water, hydrogen and oxygen are combined in the ratio of _______by mass.

(a)

1:8

(b)

8:1

(c)

2:3

(d)

1:3

48. External ear (pinna )is supported by

(a)

bone

(b)

cartilage

(c)

tendon

(d)

capsule

49. Adolescence is the period of life between _____________ years of age.

(a)

10 to 16

(b)

11 to 17

(c)

11 to 19

(d)

11 to 20

50. Tux paint software is used to ________.

(a)

paint

(b)

program

(c)

scan

(d)

PDF

51. Part - B

30 x 2 = 60
52. Convert 80°C into kelvin

53. Round off the number 1.868 to two decimal places.

54. Give the general formula for the conversion of scales of temperature?

55. What do you feel when you touch a nail immediately after it is hammered into a wooden plank? Why?

56. Why more number of wheels are provided for a heavy goods - carrier?

57. The radius of curvature of a spherical mirror is 20 cm. Find its focal length.

58. Refractive index of water is 4/3 and the refractive index of glass is 3/2. Find the refractive index of glass with respect to the refractive index of water.

59. Which mirror is used in solar cookers and solar water heaters?

60. Write three properties of metalloids.

61. What is symbol of an element?

62. What are metalloids?

63. What is pollution?

64. Why photosynthesis is a chemical reaction?

65. What is photolysis?

66. Write the names of any three protozoans.

67. Which diseases can be prevented by vaccination?

68. Give any 2 living characters of virus.

69. What is mean by Binomial Nomenclature? give example.

70. Write any two economic importance of fungi.

71. What do you mean by coenocytic mycelium?

72. What is cell differentiation?

73. Define Metabolism?

74. What is an Application Software?

75. Name three types of heat transfer

76. Give some uses of electroplating.

77. Write about the reaction of nitrogen with non metals.

78. State the law of conservation of mass.

79. Differentiate axial and appendicular skeleton.

80. What is fertilization?

81. What is the use of Text Tool?

82. Part - C

20 x 3 = 60
83. What are the differences between Plane angle and solid angle?

84. Convert i) 90° into radian, ii) $\frac { \pi }{ 6 }$ into degrees.

85. A bubble rises from the bottom of a pond to its surface by increasing its radius by 3 times its value when it was at the bottom. Calculate the depth of the pond. (Hint: Pressure depends on the depth of the pond. Volume is inversely related to pressure.) [Science Olympiad]

86. Why dams are made stronger and thicker at the bottom than at the top?

87. Define the refractive index of a medium.

88. Where the multiple reflection takes place.

89. Name the elements for following symbols.
a) Na b) W c) Ba d) Al e) U

90. What is a compound? Give example.

91. Justify the statement. Burning of fossil fuels is responsible for global warming.

92. Write the chemical substances responsible for air pollution?

93. What are pathogens?

94. What do you know about pasteurization?

95. Write any four characters of pteridophytes.

96. What is claviceps purpunya?

97. Define Prokaryotic cell?

98. What is respiration?

99. What is a Computer?

100. Explain the working of thermos flask.

101. What is electroscope? Explain how it works?

102. How is the skeleton of a bird well-suited for flying?

103. Part - D

10 x 5 = 50
104. Explain how will you measure the current in an electric circuit using circuit diagram

105. Explain Manometer with the diagram

106. What are the uses of convex mirrors?

107. Explain the biological effects of chemical reactions

108. Write a note on techniques followed in food preservation.

109. Explain the structure of an animal cell.

110. Which one of the following statements about thermal conductivity is correct? Give reason.
a) Steel > Wood > Water
b) Steel > Water > Wood
c) Water > Steel > Wood
d) Water > Wood > Steel

111. It is said that sleeping beneath the tree during night is bad for health. What is the reason?

112. What is a streamlined body? How does it help in the movement of animals that fly or swim in water?

113. What can you suggest to your classmates to keep himself / herself clean and healthy?

114. 1 x 5 = 5
115. An iron ball requires 1000 J of heat to raise its temperature by 20°C. Calculate the heat capacity of the ball.