Science, asked by Anonymous, 11 months ago

class 8th cbse periodic test-2 science question paper

Answers

Answered by Anonymous

Explanation:

SECTION – A (1 mark each)

FILL IN THE BLANKS: (10 MARKS)

1. The process of conversion of sugar into alcohol is called _____________.

2. Melting point of most of the metals is __________ than non-metals.

3. The ________________ is the control centre of the cell.

4. ____________ is a measure of gravitational of attraction on a body.

5. The force which opposes the motion of a body is ______________.

6. Loudness of sound depends on __________ of vibration.

7. Electrolysis is used for ___________ one metal over another metal.

8. The body which possesses electric charge on it, is called _______________ .

9. Meteors which reach on the earth without getting completely burnt are called ____________.

10. CFCs converts ____________ to oxygen.

MULTIPLE CHOICE QUESTIONS: (10 marks)

11. Which group of micro-organisms contain only pathogenic members?

(a) Viruses (b) Bacteria (c) Fungi (d) Algae

12. Metals can be drawn into thin wires because —

(a) They are sonorous (b) They are malleable

13. The cell organelle responsible for secretion of materials like protein, enzymes and hormones

from the cell is

(a) golgi complex (b) lysosomes (c) endoplasmic reticulum (d) nucleus

14. The force we use while running is

(a) magnetic force (b) muscular force (c) frictional force (d) gravitational force

15. The force of friction between two bodies is —

(a) Parallel to the contact surface. (b) Perpendicular to the contact surface.

16. High pitch notes are produced by stringed instruments when

(a) strings are short (b) strings are thin

17. Protons are

(a) negatively charged particles. (b) uncharged particles.

18. An INSAT picture shows a circular mass of clouds that will indicate a/an

(a) cyclone (b) tsunami (c) forest fire (d) earthquake

19. What will be the angle of incidence if a ray of light is reflected back at an angle of 30º?

(a) 60º (b) 75º (c) 30º (d) 15º

20. The next nearest star from Earth after Sun is

(a) Ursa Major (b) Ursa Minor (c) Orion (d) Alpha Centauri

SECTION – B (2 marks each))

21. What is retting?

22. What are noble metals? Give one example.

23. What are lubricants? Mention its importance.

24. What are ultrasonic vibrations? How is it important?

25. What are the laws of reflection?

26. What is an artificial satellite?

27. Differentiate between: Force and gravity.

28. Define lightning.

SECTION – C (3 marks each)

29. How is bacteria classified on the basis of their shape? Give one example of each.

30. What is a displacement reaction? Discuss why iron can displace copper from its salt solution but

copper cannot displace iron from its salt solution.

31. Describe the causes of build-up of carbon dioxide in the atmosphere and effect of increasing

CO2.

32. Differentiate between: Biodegradable and non-biodegradable pollutants.

33. Arrange the following metals in order of increasing reactivity :

Cu, K, Fe, Ag, Ca, Na, Zn, Au

34. Why do vehicle tyres have treads (grooves) on them ?

35. Why are the walls of a dam thickened near the base ?

36. Why does a vibrating simple pendulum not produce any sound?

SECTION – D (5 marks each)

37. When two bodies are charged by rubbing them together they acquire equal and opposite charge.

Explain.

38. What are the differences between plant and animal cells with the help of labelled diagram.

39. What are the two main defects of vision? How can they be corrected? Explain with diagram.

40. Match the following:

Column A Column B

1. Sodium chloride (i) copper

2. Lead nitrate (ii) silver

3. Copper sulphate (iii) aluminium

4. Silver nitrate (iv) lead

5. Aluminium chloride (v) hydrogen gas