Term 2 - Summative Assessment

Science (Theory)

Question Paper Set - 2

Instructions:

1. The question paper consists of two sections, A and B. You are to attempt both the sections.
2. All questions are compulsory.
   
3. There is no overall choice. However, internal choice has been provided in all the three questions of five marks each. You have to attempt only one option in each question.
4. All questions in Section A and all questions in Section B are to be attempted separately.
5. Question numbers 1 to 4 in Section A carry 1 mark each. These are to be answered in one word or one sentence each.
6. Question numbers 5 to 13 carry 2 marks each. These are to be answered in about 30 words each.
7. Question numbers 14 to 22 carry 3 marks each. These are to be answered in about 50 words each.
8. Question numbers 23 to 25 carry 5 marks each. These are to be answered in about 70 words each.
9. Question numbers 26 to 41 in Section B are multiple-choice questions based on practical skills. Each question carries one mark. You are to choose the correct option from among those given.

Section A

1. What is the work done on a body moving in a circular path?
2. How many erg make a joule?
3. What happens if the ozone layer covering the earth is completely depleted?
4. Name any two fossil fuels formed from dead plant and animal remains in the soil.
5. Calculate the number of oxygen atoms in two moles of sulphuric acid.
6. What is the drawback of Rutherford’s model of the atom?
7. Write any two differences between amphibians and reptiles.
8. Write the different kingdoms included under Whittaker’s classification.
9. A sealed cold drink tin of 400 g mass has a volume of 300 cm³. Calculate the density of the tin bottle.
10. a) Why does ice float on water?
    b) How is a heavy ship able to float on water?
11. a) What is the normal audible range of the human ear?
    b) What is infrasonic sound?
12. Write any two causes of air pollution.
13. Why does land near water bodies get colder faster at night?

14. a) Explain the difference between the symbols 4 P and P_4.

    b) Predict the formulae for the compounds that contain the following pairs of ions:

    (i) Fe³⁺ and SO₄^2- (ii) Na⁺ and CO₃^2- _.

    c) Calculate the molecular mass of aspirin, C₉H₈O₄ (atomic mass: H = 1, C = 12, O = 16).

15. Convert the following into moles:

    (i) 150 g of CaCO₃

    (ii) 16 g of O₂

    (iii) 3.011 × 10²⁴ atoms of sulphur (atomic mass: Ca = 40, C = 12, O = 16, S = 32)

16. The diagram given here shows some characteristic features of two divisions. Identify them and write any three differences between them.

    

    
    
17. Describe the AIDS disease.
18. Describe any three modes of entry of microbes that decide the site of manifestation within an organ or tissue.
19. Explain the following terms:

    a)Inflammation

    b) Immune system

    c) Vaccine

20. a) An object of mass 40 kg is raised to a height of 5 m above the ground. What is its potential

    energy?

    b) If the object is allowed to fall, find its kinetic energy:

    (i) When it is half-way down

    (ii) Just before it strikes the ground

21. Give three examples where multiple reflection of sound is used.

22. a) What is an echo?

    b) At least how far should somebody stand from a surface that reflects sound so that she can hear an echo when she claps her hands (take velocity of sound = 340 m/s)?

    c) How is this distance affected when the temperature of the air increases?

23. a) Calculate the number of electrons in a P^3- ion if the atomic weight of phosphorus is 31 u and its atomic number is 15. (1)

    b) What is the difference between ¹²C, ¹³C and ¹⁴C, and what do they represent? (1)

    c) An element is represented as . Write its electronic configuration. What valency does it exhibit? (1)

    d) Describe the features of energy levels proposed by Bohr. (2)

    Or

    a) How many nucleons are present in an atom of nobelium, ? How many electrons are present?

    How many nucleons can be considered as neutrons? (2)

    b) Explain Thomson’s model of the atom. (2)

    c) and are present in the ratio of 1:1. Calculate the average atomic mass of an atom of Br. (1)

24. What type of energy transformation that takes place in the following? (a) Motor (b) Florescent lamp (c) Generator (d) Woman drawing water from a well with a bucket (e) Waterfall

    Or

    a) Define power. What is the commercial unit of energy? (2)

    b) If there are three bulbs of 100 W each, and two motors of 1500 W each in a house, and all of them are used for five hours every day, then find the cost of the electricity consumed for the month of April, at Rs 5/- per unit. (3)

25. Describe the following

    a) Global warming

    b) Depletion of ozone layer

    c) Carbon cycle

    d) Physical and biological nitrogen fixation

    e) Oxygen cycle

    Or

    Draw a schematic representation of the water cycle. Also explain how water is replenished in the ground and in the oceans.

Section B

26. This plant shows a dominant gametophyte stage. Identify the division to which it belongs.

    

    a) Pteridophyta

    b) Thallophyta

    c) Bryophyta

    d) Gymnosperms

    
    

27. Here is an animal in which the brood pouch is seen in males. Identify the class to which this animal belongs.

    

    a) Amphibia

    b) Reptilia

    c) Mollusca

    d) Pisces

    
    

28. Identify the organisms that show hearts A, B and C.

    a) A-Whale, B- Ostrich,C-Salamander

    b) A-Salamander, B- Whale, C-Rohu

    

    c) A-Rohu, B- Salamander, C-Ostrich

    d) A-Ostrich, B-Rohu, C-Whale

    
    

29. How many teeth does a peacock have?

    a) Numerous

    b) 32

    c) 34

    d) None

30. Identify the characteristic feature of this animal that placed it under the phylum Annelida.

    

    Segmented externally by grooves and internally by septa

    a) Absence of exoskeleton

    b) True coelom

    c) Segmental nephridia

    
    

31. John observed a flatworm under a microscope, and made the following observations, except one. Identify it.

    a) Skeleton, circulatory and respiratory systems are absent

    b) Coelom is absent

    c) Suckers and hooks are present

    d) Alimentary canal has mouth and anus

32. The condition for which a solid sinks in a liquid is:

    a) The density of the solid is less than that of the liquid

    b) The density of the solid is greater than that of the liquid

    c) The density of the solid is equal to that of the liquid

    d) The volume of water displaced is greater than the volume of the solid

33. A car lift in a workshop or garage works on:

    a) Pascal's law

    b) Archimedes' principle

    c) Laws of floatation

    d) Bernoulli's principle

34. The units of density and relative density are ____ and ____, respectively.

    a) kg/m³, g/cm³

    b) g/cm³, kg/m³

    c) g/cm³, no units

    d) No unit, kg/m³

35. A force of 50 N acts on a surface of area 400 cm².The pressure exerted on the surface is:

    a) 1250 Pa

    b) 0.125 Pa

    c) 125 Pa

    d) 125 dyne/cm²

36. Which of the following experiences the greater upthrust?

    a) air balloon when immersed in water An

    b) A wooden block floating on water

    c) An iron nail when immersed in water

    d) A copper coin when immersed in kerosene

37. Which of the following properties of a solid tells us whether it can float or sink when immersed in water?

    a) Volume

    b) Mass

    c) Elasticity

    d) Density

38. The persistence of sound in an auditorium is the result of:

    a) Single reflection of sound

    b) Single refraction of sound

    c) Repeated refraction of sound

    d) Repeated reflection of sound

39. A tuning fork vibrates 256 times a second, and the sound propagates at 340 m/s. The length of each wave produced by the fork is approximately ___ m.

    a) 1.5

    b) 1.7

    c) 1.9

    d) 1.3

40. Several pebbles are dropped into a trough containing water at the rate of one pebble per second. Each pebble generates a ripple in the trough. The frequency of the ripples is ___ Hz.

    a) 1

    b) 2

    c) 3

    d) 4

41. A sound wave is incident on a cement wall in a room at an angle of 25°. The wave reflects at an angle of ___ from the plane of the wall.

    a) 25°

    b) 45°

    c) 65°

    d) 75°