Topper Sample Paper Science Class 9 3e3j31

CLASS IX SCIENCE (THEORY) SUMMATIVE ASSESSMENT TERM II SAMPLE PAPER I Time: 3 hours

M.M.: 80

General Instructions: i) ii) iii) iv) v) vi) vii) viii) ix)

The question paper comprises of two sections, A and B, you are to attempt both the sections. All questions are compulsory. There is no overall choice. However, internal choice has been provided in all the three questions of five marks category. Only one option in such questions is to be attempted. All questions of section A and all questions of section B are to be attempted separately. Question numbers1 to 4 in section A are one mark question. These are to be answered in one word or one sentence. Questions numbers 5 to 13 are two marks questions, to be answered in about 30 words. Question numbers 14 to 22 are three marks questions, to be answered in about 50 words. Question numbers 23 to 25 are five marks questions, to be answered in about 70 marks. Question numbers 26 to 41 in section B are multiple choice questions are based on practical skills. Each question is a one mark question. You are to choose one most appropriate response out of the four provided to you. SECTION A

1. Give one example where kinetic energy is transferred from one object to other. 2. A battery lights a bulb. Suggest the possible energy changes involved in the lighting process. 3.

What are the different states in which water is found during the water cycle?

4. List any two human activities that lead to an increase in the carbon dioxide content of air.

5. Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen, why? How does the speed of sound in air vary with rise in density of the medium?

6. The volume of 50 g of a substance is 20 cm. If the density of water is 1g/cm, will the substance float or sink? 7. What are polyatomic ions? Give any two examples. 8. Archimedes could find the purity of a king’s crown using buoyancy. How? 9. a. If an element M has mass number 27 and atomic number 13, how many neutrons does its atom contain? b. Define Avogadro’s constant. Give its value. 10. (a) Name any two green house gases. (b) What causes global warming? 11. Give two examples each of biodegradable and non-biodegradable pollutants. 12. Write two points of difference between gymnosperms and angiosperms. 13. List any two characteristics of division Pteridophyta that shows they are the most advanced cryptogams.

14. a. Draw a diagram depicting low pitched sound and high pitched sound. b. When a person uses deodorant spray, the other person standing at a distance would hear the sound of spraying first and the fragrance of spray would reach him later. Why so? 15.

(a) How do you define mechanical work? (b) Name and define SI unit of work? (c) What do you mean by positive and negative work? Give example.

16. Explain the working and application of a SONAR. 17. State any three postulates of Dalton’s atomic theory. 18. Calculate the number of molecules of sulphur present in 16 g of solid sulphur. 19. Give two examples of each of the following: a. Diseases which spread through air. b. Diseases which spread through water. c. Diseases which spread through insect. 20. What precautions can you take in your school to reduce the incidence of infectious diseases? Mention any three points. 21. List any two benefits of classification. Why bryophytes and pteridophytes grow in moist and shady places? 22. Explain, how HIV-AIDS virus affects and damages our body? What is an antibiotic?

23. (a) State the law of conservation of energy. (b) Name the type of energy possessed by the following: (i) stretched slinky (ii) a speeding car (iii) flowing water (iv) stretched rubber band. (c ) An object of mass 50 kg is raised to a height of 600 cm above the ground. What is its potential energy? (g = 10 m/s) Or (a) Define kinetic energy. Give examples. (b) Obtain an expression for the kinetic energy of an object of mass ‘m’ and possessing a velocity ‘v’. 24. (a) Chlorine occurs in nature in two isotopic forms with masses 35 u and 37 u in the ratio of 3:1. Calculate the average atomic mass of chlorine atom on the basis of this data. (b) Give any three uses of three isotopes. Or (a) Write three points of difference between isotopes and isobars. (b) Describe Bohr’s model of the atom? 25. a) Describe with diagram the oxygen cycle operating in nature. b) How depletion of ozone layer takes place? Or a) Define the following : (i) Ammonification (ii) Nitrification (iii) Denitrification b) State any two applications of green house effect. SECTION B 26. The least count of a spring balance is 1 g wt. When it is suspended freely without any weight attached to the hook, the pointer is just in front of second small division on the scale. The zero error is (a) -2 g wt (b) +2 g wt (c) Zero (d) +1 g wt 27. A student noted down the following observations in his note book: (i) Weight of the stone in air = 272 g wt (ii) Weight of the stone in water = 192 g wt (iii) Weight of the stone in salty water = 176 g wt The relative density of the salty water must be (a) 11/12 (b) 11/17 © 13/17 (d) 6/5 28. A student lowers a body in a liquid filled in a container. He finds that there is a maximum apparent loss in weight of the body when (a) It just touches the surface of the liquid. (b) It is completely immersed in the liquid. (c) It is partially immersed in the liquid. (d) It is partially immersed and also touches the sides of the container.

29. An object exerts a force F on a surface of surface area A. The pressure P acting on the surface is given by (a) P = F/A (b) P = A/F (c) P=FA (d) P = F/A2 30. In the experiment of verification of reflection of sound, the incident sound is directed along (a) Axis of tube. (b) Normal to the axis of the tube. (c) At an angle of 30 from the axis of the tube. (d) At an angle of 45 from the axis of the tube. 31. A student while ing laws of reflection of sound measured the angle between the incident sound wave and reflected sound wave as 110 o. The angle of reflection is (a) 110 (b) 55 © 27 (d) 0 32. On which of the following factors does the speed of propagation of a pulse in a slinky not depend upon? (a)Dimensions of slinky (b) Material of slinky © Room temperature (d) Length of the slinky 33. Reverberation produced in large auditoriums is due to : (a) Reflection of sound by windows. (b) Absorption of sound by walls. © Reflection of sound by walls and ceiling. (d) Absorption of sound by floor. 34. During the experiment on measurement of loss in weight of solid in tap water and salty solution, the maximum loss in the weight of the body is observed when(a) it touches the surface of the liquid (b) it is completely immersed in the liquid (c) it is partially immersed in the liquid (d) no difference in loss in weight in above three cases. 35. Skin is kept moist in earthworms. It helps in (a) Locomotion (b) Respiration (c) Protection (d) Both (a) and (b)

36. The feature that places them in the same phylum is: (a) Pointed head (b) Bulky thorax (c) Presence of scales (d) post anal tail

37. In the figure of an earthworm given below, the horizontal lines, throughout the body represent:

(a) (b) (c) (d)

Cells of the body. Cell walls separating the cells of the body. Vertically arranged muscles of the body. Septa separating segments of the body.

38. If we want to determine the volume of a solid by immersing it in water, the solid should be (a) lighter than water (b) heavier than water (c ) insoluble in water (d) heavier than water and insoluble in it 39. Rajiv found out the role of spiracle in a cockroach as: (a) Excretion (b) Circulation (c ) Respiration (d) Movement

40. Which animal belongs to phylum Arthropoda? A

B

C

D

(a) (b) (c) (d)

A B C D

41. A specimen of a fish was given to students to identify the externally visible chordate feature in it. The student would look for: (a) Operculum (b) notochord (c)Dorsal tubular nerve cord (d) post anal tail

Class IX SOLUTIONS TO SAMPLE PAPER I Science SECTION A 1. In the game of billiards, the player provides the kinetic energy to the cue ball by striking it with the cue stick. If the cue ball collides with another ball, it will slow down dramatically and the ball it collided with will gain speed as the kinetic energy is transferred on to it. 1 2. Chemical energy of battery  Electrical energy  Light energy + Heat energy. 1 3. The different states in which water is found during the water cycle are liquid (water), gas (water vapour) and solid (snow). 1 4. a. Combustion of wood. b. Deforestation. c. Respiration (any two; ½ x2=1) 5. In lightning process, flash and thunder are produced simultaneously. Flash is seen almost immediately because speed of light is extraordinarily large. But thunder is heard a few seconds later because speed of sound << speed of light. 1 Speed of light increases with the incarese in density of the medium.

1

6. Density of water ρw = 1 g cm-³ Mass of substance m = 50 g Volume of substance V = 20 cm³ .·.Density of substance ρs = m/V = 50g/ 20cm3 = 2.5 g cm-3 1 As the density of the substance is greater than that of water, the given substance will sink in water. 7. A group of atoms carrying a positive or a negative charge are called polyatomic ions. 1 Examples: (NH4+), (CO32-) ½ x2 8.The crown made of impure gold would displace more water than it would actually have, had it been made out of pure gold for the same volume. 1 The increase in the volume of the water displaced indicates the presence of impurities in the gold crown. 1

1

9. a. Atomic number = number of protons = 13 Mass number = number of protons + number of neutrons .·. Number of neutrons = mass number – number of protons =27-13=14 b. Avogadro constant is the actual number of particles (atoms, ions) present in 1 mole of any substance. Its value is 6.022 x 1023.

1/2 1/2 molecules or 1/2 1/2

10. (a) Carbon dioxide (CO2), methane (CH4), ozone (O3) and water vapour (H2O) green house gases. (any two, ½ x2=1) (b) The greenhouse gases do not allow heat rays to escape from the earth resulting in an increase of temperature of the earth. Hence, green house gases cause global warming. 1 11. Biodegradable pollutants-cow dung and paper (½ x2=1) Non-biodegradable pollutants-polythene, plastic and DDT (any two, ½ x2=1) 1 12. (i)

Gymnosperms

The seeds are naked.

(ii) The microspores and megaspores

Angiosperms (i) The seeds are enclosed by fruit wall. (ii) The microspores are produced in

are produced by male and female

anthers while the megaspores are

cones.

produced in ovules of the ovary in flowers. (½ x4=2)

13.(i) Plant body is thallus like. It is not differentiated into root, stem and leaves. (ii) No vascular tissue is found. (iii) Water is essential for reproduction. (iv) It includes algae, fungi and lichens. (any two, 1x2=2)

14.

1

1 The sound of spraying deodorant travels through the vibrations of air layers so it reaches first. But the fragrance of deodorant reaches the other person through actual movement of air particles, therefore takes more time. 1 15.(a) Work done on an object is defined as the magnitude of the force acting on the object multiplied by the distance moved by the object in the direction of the applied force. .·.Work (W) =constant force applied (F) x Displacement along the direction of force (s). 1 (b) SI unit of work is 1 joule (1J or 1Nm). Work is said to be 1 joule if under the influence of a force of 1N the object moves through a distance of 1m along the direction of applied force. 1 (c )Work is considered positive if the displacement of the object is along the direction of force applied. On the other hand, work is taken as negative if the displacement of the object is in the direction of force applied. As an example, work done by a man is taken positive when he moves from ground floor to second floor of his house. But work done by the same man is negative when he is descending from second floor of house to ground floor. 1

16.SONAR system consists of a transmitter and a detector and is installed on a ship or motorboat. The transmitter produces and transmits ultrasonic waves. 1 These waves travel through water and strike the object under water on the sea bed. The object reflects these waves and are sensed by the detector. The detector converts the ultrasonic waves into electrical signals. If d be the depth of the said object and v be the velocity of the ultrasonic waves in water, then the time interval between transmission and reception of ultrasonic waves will be t = 2d/v 1 By knowing the time t we can find the value of d. SONAR technique is used to determine the depth of the sea and to locate underwater hills, valleys, etc.

1

Ans.17 The postulates of Dalton’s atomic theory are: (i)

All matter is made up of very small particles called atoms.

(ii)

Atoms are indivisible particles which can neither be created nor destroyed.

(iii)

Atoms of an element are identical in mass and chemical properties.

(iv)

Atoms of different elements differ in masses and chemical properties.

(v)

Atoms combine in simple whole number ratio to form compounds. Any three (3 x 1 = 3)

Ans. 18 (a) Molecular mass of S 8 = 8 x Atomic mass of sulphur = 8 x 32 = 256 g 1/2 256 g of sulphur (S8) = 1 mole

 16 g of solid sulphur =

1x16 1  mole. 256 16

1/2 1/2

By Avogadro number, we know that 1 mole of sulphur (S8) contains = 6.022 x 1023



1/2

1 1 23 mole of sulphur (S8) contains = 6.022  10  molecules. 1/2 16 16

Hence, 16 g of solid sulphur has 0.376 x 1023 = 3.76 x 1022 molecules.

1/2

Ans. 19. i. Common cold and tuberculosis.

½, ½

ii. Jaundice and typhoid.

½, ½

iii. Malaria and dengue fever.

½, ½

Ans. 20. i. Prevent water logging to avoid mosquito breeding.

1

ii. Provision of safe drinking water.

1

iii. Periodic cleaning of toilets.

1

Ans. 21 (a) (i)

It makes study of organisms easy.

(ii)

It gives inter-relationship amongst different groups of animal.

(iii)

It gives us an idea about existing life forms.

(iv)

Classification is the base for development of other branches of biological science.

(any two ; 1x2=2)

(b) Bryophytes and pteridophytes grow in moist and shady places because they require water for fertilization.

1

Ans.22 (i) In HIV infection, the virus goes to the immune system and damages its function by attacking cells of immune system (T-cells). Gradual decrease in their number weakens our immune system. Our body can then no longer fight off the many minor infections that we face everyday. 1 Instead, every small cold can become pneumonia; minor gut infection can produce major diarrhoea with blood loss. Ultimately, these other infections kill the people suffering from HIV-AlDS. (ii)

1

Antibiotics are chemical substances obtained from some microbes such as bacteria and fungi, which stop the growth of specific kinds of microbes.

1

Ans.23 (a) According to the law of conservation of energy, we can neither create nor destroy energy. Energy may only be transformed from one form to another such that total energy before and after the transformation remains exactly the same. 1 (b) (i) A stretched slinky possesses potential energy on of change in its configuration. (ii) A speeding car possesses kinetic energy due to its state of motion. (iii) Flowing water possesses kinetic energy. (iv) A stretched rubber band possesses potential energy due to change in its configuration. 2 (c) Here mass of object m = 50 kg Acceleration due to gravity g = 10 m s-2 Height to which object is raised h = 600 cm = 6 m

 Potential energy of the object Ep = mgh = 50 x 10 x 6 =3000J

2

Or Ans. 23 (a) Kinetic energy of an object is the.energy possessed by it by virtue of its state of motion. A speeding vehicle, a rolling stone, a flying aircraft, flowing water, blowing wind, a running athlete possess kinetic energy. '

2

(b) Consider an object of mass m in a state of motion with an initial velocity u. Let now a constant force F acts on it and displaces the body through a distance 5 in the direction of force applied. :. Work done on the object W = Fs 1 Due to the work done on the body a change in velocity takes place. Let velocity of the object changes from u to v. Let a be the acceleration produced. Then according to the equation of motion

 2  u 2  2as

 2  u2 2a 1

Again according to second law of motion, we have F = ma

 2  u2  1    m( 2  u 2 ) ,  2a  2

Work done on the object W = Fs = (ma)

If the object started from rest, then u = 0 and hence

1 m 2 2

W

Obviously the work done on the object is equal to the kinetic energy imparted to the object. Thus, the kinetic energy possessed by an object of mass m moving with a uniform velocity



is given by

Ek 

1 m 2 2

1

Ans.24 a) The isotopes of chlorine are in the ratio 3:1. It means that the two isotopes are 75% and 25% respectively. Average atomic mass of cholorine =

35 x75 37 x 25  100 100 = 105  37 4 4 =

142  35.5u 4

1/2 1/2 1/2 1/2

b)Three uses of isotopes: (i)

An isotope of cobalt is used in the treatment of cancer.

(ii)

An isotope of iodine is used in the treatment of goiter.

(iii) An isotope of uranium is used as a fuel in unclear reactors. OR

1 1 1

(a) Isotopes

Isobars

1. Atoms of the same element having

1. Atoms of different elements having

same atomic number but different mass

different atomic number but same mass

number.

number.

2. They have same chemical properties

2. They possess different physical and

but different physical properties.

chemical properties.

1

3. Example - 1H and

2 1

H

3. Example -

40 20

Ca and

40 18

Ar 1x3=3

(b) Bohr’s model of atom I. Only certail special orbits known as discrete orbits of electrons, are allowed inside the atom.Electrons revolve around the nucleus in discrete orbits or stationary states. II.

These orbits or shells are called energy levels.The energy levels are numbered as 1, 2, 3, 4, etc. The energy levels can also be represented by the letters K, L, M, N, etc.

III.

While revolving in discrete orbits, the electrons do not radiate energy.

IV.

So long as an electron revolves in a particular orbit, it neither emits nor absorbs energy.

Ans25. a)

4x½=2

Oxygen-cycle: Oxygen from the atmosphere is used up in combustion,

respiration and in the formation of oxides of nitrogen.

½

It is returned to the atmosphere through photosynthesis.

½

2

(b)Chlorofluorocarbons used as solvents, refrigerants, propellants and blowing agents for plastic foams are stable and persist in atmosphere for years. 1 These enter the upper layers of atmosphere where UV radiation causes CFCs to dissociate the ozone into oxygen.

1

Or a) i)

Ammonification is defined as the conversion of organic material of plants and animals into ammonia and amino acids by microorganisms. 1

ii) Nitrification is defined as the conversion of ammonia into nitrates by microorganisms.

1

iii) Denitrification is defined as the conversion of nitrate into ammonia and free nitrogen by microorganisms.

1

b) Applications of green house effect: i) In cold climatic conditions, vegetables and plants are grown in glass house to protect them from cold. 1 ii) It is useful in increasing temperature in black box of solar cookers by covering it with plain glass sheet. 1

26. b 27. d 28. b 29. a 30. a 31. b 32. d 33. c

34. b 35. b 36. d 37. d 38. d 39. c 40. d 41. d