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Previous year question paper with solutions for SCIENCE Mar-2017
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Question paper 1
1. Define main focus of a convex lens.
Answer:
Main focus of convex lens:
The point at which beam of light coming from outside converges in known as focus of convex lens. The distance between center of lens and focus is known as focal length of lens.2. Write symbols for a Electric cell and wire crossing without joining.
Answer:
Symbol of electric cell and wire crossing without joining:
3. What do all acids and bases have in common ?
Answer:
Acid and bases each can produce one part of water molecule so water is common in acids and bases.
4. Define malleability ?
Answer:
Malleability:
It is the ability of a metal to be deformed in any shape.5. Define autotrophic nutrition.
Answer:
Autotrophic nutrition:
It is the process in which organism prepares their food from the simple organic materials like water minerals salts and Co2 in the presence of sunlight. The organism which produces their own food is known as autotrophs
Eg. Plants, cyanobacteria are autotrophy.6. What are fossils ?
Answer:
Fossils :
A Fossil is any preserved remains, impression of any living thing from a past geological age. Eg. Bones, Skeletons etc.7. What are biodegradable wastes ?
Answer:
Biodegradable waste:
It is the waste which can be degraded by natural factors like microbes, temperature, UV etc. Eg: Food material, natural waste. Etc.PART B
8. 6Ω, 8Ω, and 10Ω resistances are connected in series. Find total resistance of the circuit.
Answer:
Total resistor in series in given by =
RT = R1 + R2 + R3……Rn
Here
R1 = 8 Ω
R2= 6 Ω
R3 = 10 Ω
RT=8+6+10
=24Ω Ans9. Why is Sodium stored under kerosine ?
Answer:
Sodium is a very reactive metal that reacts quickly when exposed to air or water. So it needs to be stored in kerosene.
10. How do metallic character and valency of elements change in a period moving left to right in modern periodic table ?
Answer:
Metallic character decreases as atomic radius increases due to increase in valence electrons.
11. What are dental caries ? How are they caused ?
Answer:
Dental caries
It is also known as tooth decay or a cavity is a disease where bacterial processes change carbohydrates left on teeth to acid that demineralized hard tooth structure if demineralization exudes saliva and other remineralisation like from calcium, thus tissues progressively breakdown, producing cavities, holes in teeth.Two groups of bacteria is responsible for initiating cause:
(i) Streptococcus matins
(ii) Canto bacillus12. Why is the depletion of ozone layer a matter of concern for us ? What steps have been taken to minimise it ?
Answer:
Ozone layer depletion is a cause of concur because it causes the greenhouse effect and thus increasing earth’s temperature causing global warming. Due to drastic increase in temperature the glaciers and the polar ice is melting resulting increase in sea level. If this continues so then in future most of land would get immersed completely in water or certain diseases will be produced in the environment like as skin cancer this is generally due to use of chlorofluorocarbons.
Steps to limits this damage:
(i) Reduce the use of C.F.C.S in air conditioners.
(ii) Use eco-friendly household cleaning products.
(iii) Banning use of dangerous nitrous oxides.Steps have been taken to reduce ozone layer depletion
(i)In 1987, untied nation environment programme succeeds in forging an agreement to freeze CFC production at 1986 levels it is now mandatory for all manufacturing companies to make CFC- free refrigerators
(ii) Introduction of application of bio-control agents for controlling the plant pestsPART C
13. What is a wind mill ? Write its advantages.
Answer:
Windmill :
A windmill is a structure which produces electrical energy from kinetic energy of wind. It consists of mainly three components, blader, rotor and a generator. 3 blades are attached to rotor which is placed on a tower that high above the ground.
Various advantages of wind mill is as fallow:
(i) No more greenhouse gases- turbines don’t emit CO2
(ii)Power of free- no government agency can presently regulate wind so they cannot charge fees to those who choose to use it as an alternative source of life-sustaining and life-saving energy
(iii) Ease of setup
(iv) As renewable energy, it can be reproduced continuously until there is enough power to feed its designated locations.
(v) clean source of energy.14. Explain Fleming's left hand rule with the help of labelled diagram
Answer:
Fleming left hand rule :
According to this rule when we stretch the thumb, fore finger, middle finger of our left hand such they are mutually perpendicular. If the forefinger points in the direction of magnetic field and middle finger in the direction of current then thumb will point in the direction of motion or force acting on conductor.
15. Write chemical formula of Plaster of Paris (POP) and its advantages also.
Answer:
Chemical formula of plaster of Paris:
CaSo4
H2O
Advantages of plaster of Paris (POP) :
(i) It is light in weight and more disabled.
(ii) It has low thermal conductivity
(iii) It can be molded be into any shape.
(iv) It has good adhesion on fibrous material.
(v) It has no appreciable chemical action on paints and does not cause alkali attack.16. Write balanced chemical equation with the help of chemical symbols and formulas for following reactions :
(i) Zinc + Silver nitrate --> Zinc nitrate + Silver
(ii) Copper oxide + Hydrogen --> Copper + Water
(iii) Barium chloride + Aluminium sulphate -+ Barium sulphate + Aluminium chloride
Answer:
(i) Zn + 2AgNo3 → 2Ag + Zn(No3)2
Zinc silver nitrate silver Zincnitrate(ii) CuO + H2
Cu + H2O
Copper oxide hydrogen copper Water(iii) 3BaCl2 + Al2 (So4)3 → 3BaSo4 + 2AlCl3
(aq) (aq) (S) (aq)
Barium Aluminium Barium Aluminium
chloride Sulphalt Sulphate Chloride17. Draw a labelled diagram of internal structure of human heart.
Answer:
18. How is short sightedness (Myopia) caused ? How it can be corrected ? Explain with diagram.
Answer:
Myopia or short sightedness
It is that defect of vision to which a person cannot see the distant objects clearly through he can see nearby object clearly. This eye defect can be corrected by using a concave lens.
Causes:
When eyeball is longer than normal.
Cornea is more caved than normal.19. Write characteristics of an ideal fuel.
Answer:
Characteristics of an ideal fluid.
(i) It should have high calorific value.
(ii) It should have proper ignition temperature.
(iii) Rate of combustion should be balanced.
(iv) Fuel should be easily available.
(v) It should have low cost.
(vi) Content of non-volatile substance should be low.
(vii) There should be no poisonous or residue by product on combustion.
(viii) It should be easy to store.
(ix) Easy to transport.
(x) Easy to handleOR
19. With the help of a labelled diagram explain principle, construction and working of an electric . generator (Dynamo).
Answer:
Principal of working of electric generator (dynamo):
It is based on the phenomenon of electromagnetic induction.
Construction:
A simple A.C. generator consists of rectangular coil which can be rotated rapidly between poles N and S of strong horse shoe type permanent magnet. The coil is made of a large number of turn insulated cooper. The two ends of rectangular coil. Are connected to two circular pieces of copper metal called slip rings R1 and R2. As the slip ring rotates, the two fixed brushes B1 and B2 keep contact with them. So current produced in the rotating coil can be tapped out through slip rings. The outer end of brushes are connected to a galvanometer to show the flow of current in external circuit.Working:
Suppose coil ABCD is rotated in an anticlockwise direction. The side AB of coil mouse down and side CO moues up Due to this induced current is produced in both side which flows according to Fleming right hand rule. Thus in first half rotation, the current in the external circuit flows from brush B1 to B2 After half revolution, side AB and CD will interchange their portion. As a result direction of induced current in the coil is reversed. The current in external circuit flows from B2 to B1.20. What is an acid ? Write four properties of acids by giving examples.
Answer:
Acid:
Those chemical substances which have a sour taste is known as acid. Or
Those chemical substances having pH less 7 is known as acid
Eg: Acetic acid, hydro chloric Acid
(CH3CooH) (H.CL)
Properties of acid:
(i) Acid changes the color blue litmus to red.
(ii) It has pH value less than 7.
(iii) It produces salt when combined with base.
(iv) They conduct electricity when dissolved in water.OR
20. Write three chemical properties of Ethanol. Why is it used as a fuel?
Answer:
Propertius of ethanol:
(i) Ethanol is a volatile, colorless liquid that has a slight odor.
(ii) it burns with smoke blue flame.
(iii) Triple point for ethanol is 150 K at a pressure of 4.3x10-4 Pa
It is used as a fuel due to having renewable domestically produced alcohol fuel made from plants. It can reduce greenhouse gas emissions.21. What changes occur among boys and girls during adolescence ?
Answer:
Changes occur during adolescence in boys:
(i) Hair grows under armpits, public region between the thighs, chest and face.
(ii) Body becomes more muscular due to development of muscular.
(iii) The voice deepens.
(iv) Chest and shoulder broader.
(v) The penis and testes become larger.
(vi) Feeling and sexual drives associated with adulthood begin to develop.Changes occur during adolescence in girls:
(i) Hair grows under armpits, public region
(ii) Mammary gland develop and breast become enlarged.
(iii) Hip broadens and extra fat is deported in various parts of body like hips and thighs.
(iv) Fallopian tube, uterus and vagina enlarge.
(v) Ovaries start to release eggs and mensuration starts.
(vi) Feeling and sexual drives associated with adulthood begin to develop.OR
What changes can you suggest to make your house eco-friendly ?
Answer:
Following steps should be taken to make my house eco-friendly.
(a) Install solar panels: It will reduce to consumption of non-renewable sours of energy.
(b) Insulate: Use little energy as possible
(c) Buy recycled: It’s a good idea to try to buy recycled products you can.
(d) Less use of non-biodegradable products: It will lead to reduce the pollution caused by non-biodegradable products
(e) Use of 3 R’s: That means we should use the slogan or word Recycle, Re-use, Reduce
(f) Use of LEDs: It consumes less energy as compared to bulbs having tungsten or ordinary bulbs.
Question paper 2
1. Define radius of curvature of a spherical mirror.
Answer:
2. . Write symbols for (i) Resistance and (ii) Ammeter.
Answer:
3. Why curd and more sour eatables should not be kept in brass or copper utensils ?
Answer:
4. Define ductility
Answer:
5. Define Heterotrophic nutrition
Answer:
6. What'are homologous organs ?
Answer:
7. What are dominanttraits ?
Answer:
8. 5Q, 8Q and 12Q resistance are connected in series. Find resultant resistance of circuit
Answer:
9. What is an alloy ? Why is it made ?
Answer:
10. How do (i) Atomic size (ii) Metallic characters change in a group going top to bonom in modern periodic table ?
Answer:
11. Define Photosynthesis. Also write equation for it
Answer:
12. How does a developing embryo get nutrition from its mother ?
Answer:
13. How is Solar Cell Panel made ? Explain with the help of a diagram.
Answer:
14. Write three properties of magnetic field lines.
Answer:
15. Write equation for preparation of bleaching powder. Also write its advantages.
Answer:
16. Complete following reactions :
(i) Calciumhydroxide + Carbondioxide --+........ + ........
(ii) Sodium + Water -+ ........ + ........
(iii) Hydrogen + Chlorine --)........
Answer:
17. Draw a labelled diagram of Human excretory system.
Answer:
18. How is long sightedness [Hypermetropia] caused ? How it can be corrected ? Explain with the help of diagram.
Answer:
19. Wilth the help of a labelled diagram, explain the construction and working of a dome shaped bioea-s plant.
Answer:
20. What is Homologous series ? Write its two characteristics. Also write formulae of first two nrember of alkane series.
or
With the help of a labeiled diagram prove by an experiment that airloxygen and water are necessary for rusting of iron.
Answer:
21. With the help of a labelled diagram explain various parts of a flower.
or
With the help of a labelled diagram explain various parts of Human brain.
Answer:
Question paper 3
1. Define focal length of a lens.
Answer:
2. write symbols for a battery or combination of cells and a wire joint.
Answer:
3. Which acid is present in Thmarind and Ant sting ?
Answer:
4, Why do we apply paint on iron articles ?
Answer:
5. Define Pollination.
Answer:
6. Which part of brain maintain posture and equilibrium of body ?
Answer:
7. What are Analogous Organs ?
Answer:
8. How should 4Q, 8C2, 12C, and}4{lresistances be connected to get maximum resistance ? Also find the resultant resistance.
Answer:
9. How do the trend (i) Atomic size (ii) Metallic character changes in moving left to right in a period in modern periodic table ?
Answer:
10. Differentiate between Roasting and Calcination giving examples.
Answer:
11. What is a food chain ? Give example.
Answer:
12. Write two differences between aerobic and anaerobic respiration.
Answer:
13. How is electricity produced at a hydel power plant ? Explain with the help of a diagram.
Answer:
14. Write sign conventions used for reflection by spherical mirror
Answer:
15. Write chemical name and formula of washing soda. Also write its advantages.
Answer:
16. Convertfollowing statements into chemical equations using symbols and formulas and balance them.
(i) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
(ii) Hydrogen sulphide gas burns in airloxygen to produce water and sulphur dioxide gas.
(iii) Hydrogen gas with nitrogen reacts to give ammonia.
Answer:
17. Draw a labelted diagram of human female reproductive organs.
Answer:
18. Why should we conserve forests and wild life ?
Answer:
19. Explain principle, construction and working of a solar cooker with the help of labelled diagram.
or
With the help of a labelled diagram explain principle, construction and working of an electric
Answer:
20. Write differences between metals and non-metals
or
What are the properties of carbon which lead to the huge number of carbon compounds we see around us?
Answer:
21. Explain human digestive system with the help of a labelled diagram.
or
What can you do as an individual to reduce yourconsumption of the various natural resources ?
Answer: