CBSE Board Class 9 Science Previous Year Question Papers 2011

PREVIOUS YEAR PAPER-2011
SCIENCE

class  9
Max Marks – 80       Time – 3 hours.
General Instructions :
i)The question paper comprises of two sections, A and B. You are to attempt both the sections.
ii)All questions are compulsory.
iii)There is no overall choice. However, internal choice has been provided in all the five questions of five mark category. Only one option in such questions is to be attempted.
iv)All questions of section A and all questions of section B are to be attempted separately.
v)Questions number 1 to 3 in section A are one mark questions. These are to be answered in one word or in one sentence.
vi)Questions number 4 to 7 in section A are two marks questions. These are to be answered in about 30 words each.
vii)Question number 8 to 19 in section A are three marks questions. These are to be answered in about 50 words each.
viii)Questions number 20 to 24 in section A are five marks questions. These are to be answered in about 70 words each.
ix)Questions number 25 to 42 in section B are multiple choice questions based on practical skills. Each questions is a one mark question. You are to select one most appropriate response out of the four provided to you.
SECTION – A

1.A body does 50J of work in 5 seconds. What is its power?

2.A standing man holding a suitcase in his hand. State if work is done or not done. Why?

3.Name the major Green house gas responsible for causing global warming.

4.A fish weighs less in water than air. Why?

5.Define wavelength and amplitude.

6.Differentiate Kinetic energy and Potential energy. (2 points)

7. Element Atomic Number of neutrons
X        Y
37     20
35     18
a)Write atomic number and electronic configuration of X
b)What is the relation between the two species X and Y

8.A bat emits ultrasonic sound of frequency 100 KHz in air. If his sound meets Water surface, what is the wavelength of
i)Reflected sound  ii)  transmitted sound
Given : speed of sound in air = 340 m/s and in water = 1486 m/s

9.Derive the expression for kinetic energy, K. E = ½ m v2 and the symbols have their usual meanings.

10. a) State Archimedes’s principle of floatation.
b) Relative density of silver is 10.9. The density of water is 103 kg m-3. What is the density of silver in S.I. unit.

11.a) State the law of constant proportions
b) Two grams of hydrogen combine with 16 grams of oxygen to form water. How many grams of water will be formed? Write the name of law of chemical combination which you have used in the calculation.

12.a. A flask contains 180 grams of water, Calculate
i)The number of molecules present in water?
ii)How many moles does it contain?
b. Calculate the mass of 54.18 x 1023 molecules of carbon dioxide.

13.Pick the odd one out and justify your choice by giving reasons
i)Crocodile, Pigeon, Rat, Toad
ii)Funaria, Marchantia, Riccia, Fern

14.Distinguish between acute diseases and chronic diseases. Give an example for each.

15.A person gets a disease like cholera

16.Give the scientific term for the following
a)A substance that is injected into the body to protect against a specific disease
b)A chemical substance obtained from microbes to stop the growth of specific kinds of microbes
c)The body part of the host where a pathogen attacks and manifests the symptoms of the diseases.

17.State the major characteristic considered for classifying the organisms.

18.What is nitrogen fixation? How is it carried in nature?

19.Distinguish power from energy. Write their commercial units. An electric heater of 1000 W is used for 2 hours a day. What is the cost of using it, for a month of 28 days, if one unit costs  3?

20.(a) What is SONAR? What is the basic principle of its working? Explain its use.
(b) Why do the stages of auditorium have curved background? Curtains, carpets and false ceilings?       OR
(a)What is meant by positive work and negative work? Illustrate with an example for each.
(b)A horse and calf are running with same speed. Which of the two has more kinetic energy? Draw a graph to show relation between mass and K.E of a moving body.

21.a) Explain Rutherford’s experiment with his observations and result
b) What is the valency of an element if it’s atomic number = 12?
What is the name of this element?     OR
a)Summarize the three rules for writing of distribution of electrons in various shells for the first elements?
b)X contains 11 proton and 12 neutrons. Identify the element and write its electronic configuration

22.a) With the help of diagram show Nitrogen cycle in nature
b) What is the importance of nitrogen fixing bacteria?   OR
a)With the help of a labeled diagram show the cycling of oxygen in nature.
b)Name a harmful synthetic chemical which is mainly responsible for depletion of ozone layer.

23.Does sound require a medium to pass? Explosion in stellar space is not audible on the surface of earth. Give reason.

24.a) What are postulates of Bohr’s model of atom?
b) What are α-particles?