Sunday, November 29, 2015

Biology class IX Ch-07. Diversity in Living Organisms solved Questions New

Diversity in Living Organisms solved CBSE Paper-5

Oswal Question Bank Diversity in Living Organisms        Download File

Very Answer type Questions [1 mark each]  


1.State the phylum to which centipede and prawn belong. (Board 2013)

Answer: Arthropoda.         

2. In which kingdom would you place an organism which is single called, eukaryotic and photo-
synthetic? (Board 2013)

Answer:  Protista.

3.Rewrite the scientific name correctly : (i) panthera tigris (ii) periplaneta Americana. (Board 2012., 
501004)

Answer:  (i) Panthers tign's  (ii) Periplaneta americana.

4.Name the term which is used for the following

(i) The left and right halves of the body have the same design.

(ii) Animal tissue defferentiate from the three embryonic germ layers. (Board 2012, 501005; 47023)

Answer:  (i) Bilaterally symmetrical. (ii) Triploblastic.       

5.Name the phylum to which Prawn and Centipede belong. (Board 2012, SC-1008; 47001,) 

Answer:  Arthropoda.

6. Mention the function and location of notochord.

Answer:  Functionn—lt provides a place for muscle to attach for ease of movement.

Location—runs along the back of the animal separating the nervous tissue from the gut.

7. State the phylum to which Antedon (feather star ] and Asterias (Starfish) belong. (Board 2012,  501010)

Answer:  Echinodermata.

8.Mention any one characteristic feature of saprophytes. (Board 2012, 47005)

Answer:  They have cell wall made of tough compare sugars called chitin.

9.Which in your opinion is more basic characteristics for classifying organism - the place where they  live in or the kind of cells they are made of ? (Board 2012, 501006)

Answer:  The kind of cells the organisms are made of.

10. Write the name of phylum to which Hydra and Sea anemone belong.- (Board 2012, 47017)

Answer:  Coelenterata.

11. Name the phylum to which Leech and Earthworm belong. (Board 2012, 47004 }

Answer:  Annelida.

12. Name a division of plants which can be classified as cryptogarnae. (Board 2012, 47010}

Answer:  Pteridophyta / Thallophyta / Bryophyta. (Any one)

13. State the system in poriferans that heips in circulating water throughout the body to bring in food and oxygen. (Board 2012, SC-1011}

Answer:  Canal System

14. Write an example of the species which belong to this phylum and lives in colonies.

Answer:  Corals.

15. Name the phylum to which Octopus and Unio belong ?  (Board 2012, 4700}

Answer:  Mollusca.

Diversity in Living Organisms solved CBSE Paper-1
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Diversity in Living Organisms NCERT Solution
9th Diversity in Living Organisms Study Notes
9th 9th Diversity in Living World Notes                            
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Sunday, November 22, 2015

9th Sound Test Paper Solved

1.A submarine enters a sonar pulse, which returns from an under water cliff in 1.02 s. If the speed of sound in salt water is 1531 m/s, how far away is the cliff?
Ans: t = 1.02s, v = 1531m/s Now d=s x t Distance travelled by sonar pulse = 2d = 2x1531x1.02 = 1561.62m

Distance of the cliff = d/2= 1561.62/2 = 780.81m

2. If the tension in the wire is increased four times how will the velocity of wave in a string varies?
Answer: velocity of the wave in string is directly proportional to the square root of the tension thus if tension is increased 4 times the velocity will be doubled.

3. What is Echo. Explain the conditions that have to be satisfied to hear an echo?
Ans: reflection of sound wave from a large obstacle is called an echo.

The most important condition for hearing an echo is that the reflected sound should reach the ear only after a lapse of at least 0.1 second after the original sound dies off and the obstacle is at least at a distance of 17 m

4. Why do echoes produced in an empty auditorium usually decrease when it is full of audience?
Ans: When the hall is empty there is no obstacles in between to reflect the sound other than the walls. When the hall is full of audiences the sound produced undergoes multiple reflection from the people and so it overlaps with the sound produced. Hence the listener is not able to distinguish between the original sound and the echo.

5. A girl claps and hears the echo after reflection from cliff which is 660 m away. If the velocity of sound is 330 m s-1, calculate the time taken for hearing the echo. 

Ans: v x t = 2 d Þ t = 2d/v = 2x660/300 = 4s

6. Explain how is the principle of echo used by the dolphin to locate small fish as its prey.
Ans: Dolphins are aquatic animals which send out ultrasonic sound to communicate with each other. They have a sound sensing system which enables them to find animals under water with great accuracy due to the echo of the ultrasonic sound produced by them.

7. Explain by some experiment that sound waves require medium for their propagation.
Ans: An electric bell is suspended inside an airtight glass bell jar connected to a vacuum pump. As the electric bell circuit is completed, the sound is heard. Now if the air is slowly removed from the bell jar by using a vacuum pump, the intensity of sound goes on decreasing and finally no sound is heard when all the air is drawn out. We would be seeing the hammer striking the gong repeatedly. This clearly proves that sound requires a material for its propagation.

8. Distinguish between loudness and intensity of sound.
Ans: Intensity depends on the energy per unit area of the wave and it is independent of the response of the ear, but the loudness depends on energy as well as on the response of the ear.

9. Give two practical applications of the reflection of sound waves.

Ans: (i) In stethoscope the sound of patient’s heartbeat reaches the doctor’s ears by multiple reflections in the tubes.

(ii) Megaphones are designed to send sound waves in particular direction are based on the reflection of sound.

10. Why are longitudinal waves called pressure waves?

Ans: Sound waves travels in the form of compression and rarefactions, which involve change in pressure, and volume of the air. Thus they are called pressure waves.

11. Sound travels faster on a rainy day than on a dry day. Why?
Ans: Sound travels faster on rainy day because the velocity of sound increases with increase in humidity. On rainy day humidity is more thus velocity of sound is also more.

12. How moths of certain families are able to escape capture?
Ans: Moths of certain families can hear high frequency sounds (squeaks) of bat as they have sensitive hearing equipment. Thus they get to know when a bat is near by and hence able to escape its capture

Extra score 

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Thursday, October 15, 2015

9th CBSE Science Chap 3 Atoms and Molecules Self study Questions


Solved problems:Class 9 _Atoms and Molecules 

1. Q. 5 g of calcium combine with 2 g of oxygen to form a compound. Find the molecular formula of the compound. (Atomic mass of Ca = 40 u; O = 16 u) 

Ans. Number of moles in 5g of calcium = mass / molar mass    =5/40    =  0.125 
Number of moles in 2g of oxygen = mass / molar mass         =  (2 / 16)  =  0.125


Now we will calculate the simplest ratio of the element by dividing the number of moles of each element by the smallest value. 

Since number of moles of each element is 0.125, therefore calcium and oxygen are present in a ratio of 1 : 1. Thus the empirical formula of the compound is CaO.


For calculating the molecular formula, we need the molecular mass of the compound. However, because a compound with the formula CaO is known,


Therefore the molecular formula of the compound is CaO.

. Q. (i) Name the body which approves the nomenclature of elements and compounds.
(ii) The symbol of sodium is written as Na and not as S. Give reason.
(iii) Name one element which form diatomic and one which form tetra atomic molecules. [CBSE 2011 ]


Ans. (i) IUPAC (International Union of Pure and Applied Chemistry)
(ii) Latin name of sodium is Natrium. The first two letters (Na) of this name represents the symbol of sodium.
(iii) Oxygen forms diatomic molecules and phosphorus forms tetra atomic molecules.


3. Q. Calcium and Oxygen are combined in the rates of 5:4 by mass to form calcium oxide.  What mass of Oxygen gas would be required to react with 2.5 g of calcium ? 


Ans:  Calcium and oxygen combine in the rates of 5:4 by mass to form calcium oxide
let x gram of oxygen is required to react with 2.5 g of calcium to form calcium oxide
Therefore 5/4 = 2.5 / x 

     5 x = 2.5 x  4 
       x = (2.5 x 4 ) / 5   
So, x = 2
Therefore 2 grams of oxygen is required to react with 2.5 grams of calcium to form calcium oxide .

Problems (based on mole concept)

4.Q. a. Calculate the number of moles in 81g of aluminium

Solution : Atomic mass of Al= 27gm
     27g  of  aluminium = 1 mole of aluminium  
     81g  of aluminium   = 1/27 x 81=3 moles of aluminium  
OR, Use formula , Number of moles = given mass/atomic mass
Self: ii) 4.6g sodium   iii) 5.1g of Ammonia  iv) 90g of water v) 2g of NaOH

5. Q. Calculate the mass of 0.5 mole of iron

Solution: Atomic mass of iron = 55.9 g
Mass of the 1 mole of iron   = 55.9 g
Mass of the 0.5 mole of iron   = 0.5 x 55.9 g = 27.95 g
Or, Using formula: mass = atomic mass x number of moles
FOLLOW UP: Find the mass of 2.5 mole of oxygen atoms

6.Q.Calculate the number of molecules in 11g of CO2

Solution: gram molecular mass of CO2 = 44g
 44g of CO2  = 6.023 x 1023  molecules
1 g of CO2  = ( 6.023 x 1023 ÷ 44 g ) molecules
11g of CO= ( 6.023 x 1023 ÷ 44 g ) x 11 = 1.51 x 1023 molecules
FOLLOW UP: Calculate the number of molecules in 360g of glucose

7. Q. Calculate the mass of glucose in 2 x 1024 molecules

Solution: Gram molecular mass of glucose = 180g
Mass of glucose  [180 x 2 x 1024 ] / [6.023 x 1023  ] = 597.7g
FOLLOW UP: Calculate the mass of 12.046 x 1023 molecules in CaO.

8. Q. Calculate the number moles for a substance containing 3.0115 x 10^23 molecules in it.
Solution: Number of moles = Number of molecules/Avogadro Number

                       = [3.0115 x 1023 ] / [6.023 x 1023  ]      = 0.5 moles

9. Q. Calculate the mass of 18.069 x 1023 molecules of SO2
Solution:
Mass of a substance =  gram molecular mass x number of particles/ 6.023 x 1023
Gram molecular mass SO2 = 64g
6.023 x 1023 molecules of SO2     = 64 gm
1           molecules of SO2     = 64/(6.023 x 1023 )  gm
18.069 x 1023  molecules of SO2   = [ 64/(6.023 x 1023 )  x  18.069 x 1023  ]gm = 192 g


Other Download study links:  Chap 3 Atoms and Molecules class9

Class 9 Atoms and molecules NCERT Solutions-1
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Solved Problems (based on mole concept)
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Class 9 SA2: Atoms and molecules solved CBSE Test Papers New

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Friday, October 2, 2015

Floatation_Class-9 important solved Questions from previous year CBSE Board Paper

Fully Solved Questions from previous year board Paper
Question: 1. What causes buoyant force (or up thrust) on a boat?

Answer: Buoyant force is due to volume of boat and density of water.

Question: 2. what is the cause of buoyant force?

Answer: : The pressure difference on lower part and upper part of a body cause of buoyant force .

Question: 3. An Object of volume V is immersed in a liquid of density P. Calculate the magnitude of buoyant force acting on the object due to the liquid

Answer: Vd g

Question: 4. why does a block of wood held under water rise to the surface when released?

Answer: This happens because as upward force is greater than the weight.

Question: 5. What happens to the buoyant force as more and more volume of a solid object is immersed in a liquid. When does the buoyant force become maximum?

Answer: The buoyant force exerted by a fluid is equal to the weight of fluid displaced. Therefore the buoyant force increases as more and more volume of a solid object is immersed in a liquid.
Buoyant force is maximum when a body is completely immersed in a fluid.

Question: 6. Explain why, a piece of glass sinks in water but it floats in mercury.

Answer: The density of glass is more than water, but less then mercury, Therefore glass float on mercury and sinks in water.

Question: 7. When is the pressure on the ground more when a man is walking or when a man is standing ? Explain. 

Answer :  When a man is walking is weight is alternately on one feet or the other, when he is standing, his weight is divided on both feet. Therefore pressure is more on the ground when he is walking (as surface area is less).

Question: 8.  A solid weighs 80 g in air, 64 g in water. Calculate the relative density of solid. When kept in water, state if the object would float or sink?

Answer:  Weight loss in water = (80 -  64) g = 16
Relative density of solid = (weight in air/ Weight loss in water) = 80/16= 5
Since relative density of water is 1 which is less than that of solid. Hence Solid Sink

Question: 9. why density varies?

Answer: The density of a material depends on two things.
(i) The individual mass of each atom or molecule of substance  (ii) How tightly the atoms are packed

Question: 10. An object is suspended with a string . The string is stretched. When the object is completely immersed in water, the extension of the thread decreases. Why?

Answer : This happen because when the object is completely immersed in water it experience an upward force that cause weight loss.
More Questions are solved Here:  http://jsuniltutorial.weebly.com/
Sure shoot MCQ for class 9 science term-2 ClicK Here

IX Thrust and Pressure, Archimedes’ Principle, Relative Density
CBSE Class 9 - Science - Chapter 10: Flotation: Notes and Quest
MCQ: Flotation: Thrust, Pressure, Buoyancy and Density
Thrust and Pressure, Archimedes’ Principle, Relative Density key point
Notes : Flotation: Thrust, Pressure, Buoyancy and Density
Physics Flotation Term-II Class IX  Buoyant force Detail Study
9th Physics Solved Numerical Floating bodies

Sunday, September 6, 2015

Solved SA-1 Sample papers for class 9 [Maths and Science] New


Download and starts practicing sample papers for class 9 [Maths and Science] New

Class 9 Science S A - 1 Fully Solved Sample Question papers
9th science sa-1 toppers fully solved Sample paper-1
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Friday, September 4, 2015

Improvement in Food Resources class 9 fully solved question from CBSE Exam paper

CBSE solved ,unsolved test papers,Notes, Assignments and Guess Papers : First Term: Improvement in Food Resources. Plant and animal breeding and selection for quality improvement and management; use of fertilizers, manures; protection from pests and diseases; organic farming.

SA-I (2013) TLPEK7V

1. Mention two climatic conditions essential for different crops for growth and completion of their life cycle. 1

Ans: Temperature and photoperiods.

2. “Green Revolution of 1960 is a boon by itself”. List three steps that may be initiated to increase crop production 3

Ans: The major groups of activities for improving crop yields can be classified as:

(a) Crop variety improvement (b)Crop production improvement (c) Crop protection management.


3. In what ways internal parasites like worms and flukes and external parasites cause harm to the cattle’s. 3

Ans: External parasite – Skin diseases; worms – affect stomach and intestine; Flukes – damage liver

4. Explain the meaning of ‘milch’ and ‘draught animals. Mention the scientific name of common Indian cow. 3

Ans: Milk-producing females are called milch animals (dairy animals) like cow , while the ones used for farm labour are called draught animals like ox,donkey.

The scientific name of common Indian cow is Bos indicus

5. (a) Differentiate between mixed cropping and inter-cropping. Give one example of each.
    (b) How is crop-rotation different from the above two ?
    (c) Mention the factors that are taken into consideration for deciding choice of crops for inter     

         cropping and crop rotation. Also mention one advantage of each of these cropping patterns.

Ans: (a) In mixed cropping two or more crops are grown simultaneously. For eg wheat + gram

Inter - cropping - two or more crops are grown simultaneously on the same field in a definite pattern. For eg, soyabean +maize

(b) In crop rotation different crops are grown on a piece of land in a pre-planned succession. 

Depending upon duration of crop rotation is done for different crop combination.

(c) Inter- Cropping - crops are selected such that their nutrient requirements are different. This ensures maximum utilization of the nutrients supplied and prevents pests and diseases from spreading to all plants - thus better returns.

Crop - rotation - Availability of moisture and irrigation facilities Two or more crops can be grown in a year with good harvest

SA-I (2013) NK9FZA3

1. Mention the significance of sun hemp in the crop variety improvement process.1

Ans: Sun hemp is a green plant that turn into green manure which helps in enriching the soil in nitrogen and phosphorus.

2. What is organic farming? List its four advantages. 3

Ans: Organic farming is a farming system with minimal or no use of chemicals as fertilizers, herbicides, pesticides etc with a maximum input of organic manures.

Advantages:-

(a) Farm wastes (straw and livestock excreta) are recycled.

(b) Bio agents such as culture of blue green algal are used in the preparation of bio fertilizers.

(c) Neem leaves or turmeric is used as a bio pesticide in storage of grains.

(d) Healthy cropping systems such as mixed cropping inter cropping and crop rotation are beneficial in insect, pest and weed control besides providing nutrients.

3 (a) List three factors on which cultivation practices and crop yield depends.
   (b) Name three stages involved in farming practices. 3

Ans: (a) Biotic and abiotic resistance, change in maturity duration, wider adaptability.

        (b) Crop variety improvement, crop production improvement, crop protection management.

4. (a) Farmer A wants to grow fodder crops while farmer B wants to grow cereals. Mention the agronomic characteristics which the two farmer would desire in their respective crops. 5
(b) List any four other factors for which variety improvement is done.
(c) Name and define the process of incorporating desirable characteristics into crops.


Ans: (a) For fodder crop – Tallness and profuse branching and Cereal crop - Dwarfness

(b) Higher yield, biotic and abiotic resistance, changes in maturity duration, Improved quality, wider adaptability.

(c) Hybridization. : It is the process of crossing between genetically dissimilar plants.

SA-1(2014) LACWASE
1. India is a country with three fourth of the population engaged in agriculture. Even though financial conditions of some farmers do allow them to take higher level farming practices and improved agriculture technology, yet they are hesitant to use of HYV seeds with traits such as resistance to disease and pests, high quality that would results finally in higher yield. [3]

(i) What is meant by genetically modified crops ?
(ii) What are the desired agronomic characters for fodder and cereal crops ?
(iii) In your opinion what should be done so that the modern agriculture technology is adopted by most of the farmers ?


Ans: (i) To get desired traits in a crop (ii) Fodder – profuse branching, cereal – dwarfness

(iii) encourage scientific temper, awareness, use of knowledge

2. Define ‘Rain water Harvesting’ and ‘Water shed management’ and state one advantage of each. [3]

Ans: Rainwater harvesting is a technique used for collecting, storing and using rainwater for irrigation and other uses. The rainwater is collected from various hard surfaces such as roof tops and/or other manmade aboveground hard surfaces.

Watershed management: The management of water resources in an certain area. It is done to increase the utility of rainwater by building small check-dams . The check-dams stop the rainwater from flowing away and also reduce soil erosion.

3. ow does maximum utilization of available resources be ensured in composite fish farming ? Mention its limitation? Discuss how this limitation of composite fish culture can be overcome? [5]

Ans: The maximum utilization of available resources be ensured in composite fish farming by using of number of fish varieties in a single pond to prevent competition for resources. Each one must have different feeding zones.

Limitation – The major problem in fish farming is the lack of availability of good quality seed.

To overcome this problem, fishes are allowed to breed in ponds using hormonal stimulation. This has ensured the supply of pure fish seed in desired quantities.

4. what is hormonal stimulation in fish and how is it done in fish?
Ans: Hormonal stimulation of fishes is done to mature sex cells artificially. Hormones and methods used for stimulation slightly vary for different species of fishes. Hormone that could be used for stimulation is Luteinizing hormone (LH) that trigger ovulation.

5. In an experiment to test the presence of starch in a sample of food the wrong step is :[1]

(a) Take foodstuff like potato or rice
(b) Crush food in boiling water
(c) Add iodine powder in test tube (Ans)
(d) Pour mixture in the test tube

6. Rohit was trying to test the presence of starch in potato extract. He forgot the reagent with which starch gives blue black colour. Help him to select the correct stain from the following :[1]

(a) Safranin 
 (b) Methylene blue
c) Iodine solution (ans) 
 (d) Eosin

7. What do you mean by the term sustainable development?

Ans: Sustainable development means to meet the needs of present generation ,without foreclosing the options of future generation, to keep balance between development and environment.

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SA-1(2014) 7 EKSMTL

1. Sohnapur, a small village, where crops were dependent on rain. Villagers were at the mercy of monsoon. To prevent crop failure they discussed the matter in the panchayat and wanted to do some havan to appease Rain Gods. But Rakesh who was studying in class IX, advised all of them to adopt measures for conserving water and stop crop failure.
(i) If there is low rainfall in a village throughout the year. List at least two measures by which farmers can prevent crop failure in future.
(ii) List two traditional ways of conserving water for irrigation.
(iii) Write two values of Rakesh that have helped the villagers to sail through the difficult times. [3]


Ans: (i) enrich soil with humus to increase water holding capacity, use of drought resistant varieties

(ii) Traditional methods of irrigation involve different ways of obtaining water from wells, lakes, and canals and transporting it to fields with the help of cattle or by human labour like Dhekli, chain and pump,Moat (pully system)

(iiI) critical and analytical thinking, preparedness, cooperation, team work, mutual concern, applying knowledge.

2. Explain intensive fish farming with the help of one example . Write two advantages of this pences. [3]

Ans: Intensive fish farming or in combination with a rice crop so that fish are grown in the water in the paddy field. Both local and imported fish species are used in such system.

Advantages of this process :

(i) Maximum use of resources. (ii) Increase the yield.

3. Define ‘Hybridisation’. Explain the three types of cross-breeding practiced during hybridisation ? What do you mean by genetically modified crops ?

Ans: Hybridisation is way of crossing between genetically dissimilar plants.

a. Intervarietal Hybridization: way of crossing between different varieties

b. Interspecific Hybridization : way of crossing between different species

c. Intergeneric Hybridization : way of crossing between different genera

Genetically Modified Crops (GMC).: Another way of improving the crop is by introducing a gene that would provide the desired characteristic.

4. In a sample of food iodine solution is used to detect the presence of :

(a) Proteins
(b) Starch (ans)
(c) Sugar
(d) Fats

5.Yellow brown colour is the colour of a reagent named :

(a) dil HCl 
 (b) safranin
(c) Iodine solution (ans)
(d) dil sodium hydroxide

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Thursday, September 3, 2015

Basic Science Class 8 Solution by Jsunil

We are providing you scanned copy of exercise so that you can check your study chapters are:
1. Food production     2.The cell  3. Micro organism   4. Reproduction  5. Synthetic Material
6. Metal and non metals  7.Combustion and Flame  8.Force and Pressure
Some of them are here
Basic Science Question Answer Class 8 Bharati Bhawan Publication 

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Sunday, August 30, 2015

SA-1 class 10 Sample Paper of Science Sept. 2015 New addition

U-Like CBSE CCE Sample Papers AS CBSE sample papers have many advantages.
These papers give students an idea of the pattern of the paper and help them evaluate their preparedness for the exams. Understanding the CBSE marking scheme and the types of questions are two very big advantages as well.

Fully solved paper by Jsunil Tutorial
Class X Science SA-1 Solved Question paper 2014-1

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SA-1 class 10 Sample Paper of Science Sept. 2015 New addition


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Sunday, August 23, 2015

Class- (10)X-Mathematics : Summative Assessment I (SA - 1): Sample Question Paper with solution New

Class- (10)-Mathematics:  Summative Assessment I (SA -1): Sample Question Paper with solution New

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class 10 Sample Paper of Mathematics Sept. 2015

Class 10 Mathematics 2015 Sample Paper - 01

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Sunday, August 9, 2015

CBSE CLASS X Chapter 01: Chemical Reactions and Equations NCERT Activity explanation


NCERT ACTIVITIES Class 10 Chemical Reactions and Equations

Activity 1.1 (Experiment):
Aim: To show the reaction between magnesium and  oxygen present in the air.

Apparatus: Mg ribbon, watch – glass, pair of tongs,  burner, sand paper

Procedure: Clean a magnesium ribbon about 2 cm  long by rubbing it with sandpaper. Hold it with a pair of tongs Burn it using a burner and collect the ashes so formed in a watch – glass as shown in the fig.


while burning the magnesium ribbon keep it as far as possible from your eyes.

Observation: magnesium ribbon burns with a dazzling white flame and changes into a white powder.

This powder is magnesium oxide Conclusion: MgO is formed due to the reaction between magnesium and oxygen present in the  air.

Equation, 2Mg + O2 → 2MgO

Activity 1.2 (Experiment):

Aim: To show change in state and colour when a chemical reaction takes place.

Apparatus: lead nitrate solution, potassium iodide solution, test tube, and a conical flask.

Procedure: Take lead nitrate solution in a test tube Add potassium iodide solution to this.

Observation: lead nitrate reacts with potassium iodide to give lead iodide and potassium nitrate.

The colour of the products is different from that of the reactants.

Conclusion: Pb(NO3)2 + 2KI → PbI2 + 2KNO3. 

The change in colour is because lead iodide and potassium nitrate have been formed after the reaction. PbI2 is a yellow ppt. KNO3 is a colourless solution

Activity 1:3 (Experiment):

Aim: To show the interaction between zinc granules and hydrochloric acid or sulphuric acidformation of H gas)

Apparatus: Zinc granules, conical flask, test tube, hydrochloric acid / sulphuric acid

Procedure: Take a few zinc granules in a conical flask or a test tube. Add dilute hydrochloric acid or sulphuric acid to this.

Touch the conical flask or test tube.

Observation: A gas is evolved and the conical flask is warm 


Conclusion: From this we conclude that when a chemical reaction takes place there is a change in the state, colour, and temperature.

Zn + 2HCl → ZnCl2 + H2↑ + heat 

Zn + H2SO4 → ZnSO4 + H2↑ + heat

Activity 1.4 (Experiment):

Aim: Formation of slaked lime by the reaction of calcium oxide with water 

Apparatus: Calcium oxide, beaker, and water

Procedure: Take a small amount of calcium oxide or quick lime in a beaker. Slowly add water to this. Touch the beaker

Observation: The beaker becomes hot (exothermic reaction). It reacts vigorously with water.

Conclusion: Slaked lime is formed by the reaction of the combination of calcium oxide with water
CaO(s)              +            H2O(l)              →               Ca(OH)2(aq) + heat

(quick lime)                                                                 (Slaked lime) (exothermic reaction)

This is a combination reaction, and also an exothermic reaction.

Activity 1.5 (Experiment):

Aim: To show a decomposition reaction

Apparatus: ferrous sulphate crystals, dry boiling tube and burner

Procedure: Take about 2g ferrous sulphate crystals in  a dry boiling tube. Note the colour of the ferrous sulphate crystals. Heat the boiling tube over the flame of a burner or spirit lamp observe the colour of the crystals after heating

Observation: The green colour of the ferrous sulphate  crystals has changed there is also the characteristic odour of burning sulphur.

Conclusion: This is a Decomposition reaction, shown by the reaction 

2FeSO4(s) + Heat      → Fe2O3 + SO2(g) + SO3(g)

Activity 1.6 (Experiment):

Aim: Heating of lead nitrate and emission of nitrogen dioxide

Apparatus: lead nitrate powder, boiling tube, pair of tongs and burner Procedure: Take about 2 g lead nitrate powder in a boiling tube. Hold the boiling tube with a pair of tongs and heat it over a flame. Observe the change if any. 

Observation: We observe the emission of brown fumes. 

Conclusion: These fumes are of nitrogen dioxide (NO2). The reaction that takes place is

2Pb(NO3)2(s)        ---Heat→   2PbO(s)            +       4NO2(g)              +       O2(g)

(Lead nitrate)                           (Lead oxide)           (Nitrogen dioxide)        (Oxygen)
Activity 1.7 (Experiment):

Aim: To show that water is a compound  containing two atoms of hydrogen and 1 atom
of oxygen

Apparatus: Plastic mug, rubber stoppers, carbon electrodes, 6 volt battery, water, dilute sulphuric acid, burning candle 

Procedure: Take a plastic mug. Drill two holes at its base and fit rubber stoppers in these
holes. Insert carbon electrodes in these rubber stoppers as shown in fig then connect these
electrodes to a 6 volt battery. Fill the mug with water such that the electrodes are immersed.

Add a few drops of dilute sulphuric acid to the water. Take two test tubes filled with water and
invert them over the two carbon electrodes. Switch on the current and leave the apparatus undisturbed for some time. Observe the formation of bubbles at both the electrodes. These bubbles displace water in the test tubes. The volume of the gas collected is not the same in both the test tubes. Once the test tubes are filled with the respective gases, remove them carefully. 

Test these gases one by one by bringing a burning candle close to the mouth of the test tubes. 

Observation: We observe the formation of bubbles at both the electrodes. These bubbles displace water in the test tubes. The volume in one test tube is twice that in the other test tube. `The test tube containing hydrogen gas has double the volume of the test tube containing oxygen gas. Hydrogen gas burns with a light blue flame with a pop sound. 

Conclusion: Water is a compound containing two atoms of hydrogen and 1 atom of oxygen.

Activity 1.8 (Experiment):

Aim: To show how silver chloride is affected by sunlight
Apparatus: silver chloride and a china dish.  

Procedure: Place this china dish containing silver chloride in   sunlight for some time. Observe the colour of the silver chloride after some time.

Observation: White silver chloride turns grey in sunlight.

Conclusion: This is due to the decomposition of silver chloride into silver and chlorine by light

2AgCl(s)   ----Sunlight→   2Ag(s) + Cl2(g)

Activity 1.9 (Experiment):

Aim: To show displacement reaction

Apparatus: two iron nails, sand paper, copper sulphate solution, thread and two test tubes.
Procedure: Take two iron nails and clean them by rubbing them with sand paper. Take two test
tubes marked as (A) and (B). In each test tube, take about 10 ml copper sulphate solution. 

Tie one iron nail with a thread and immerse it carefully in the copper sulphate solution in test tube A
for about 20 minutes. Keep one iron nail aside for comparison. 

After 20 minutes, take out the  iron nail from the copper sulphate solution. Compare the intensity of the blue colour of copper sulphate solutions in the test tubes (A) and (B). Also, compare the colour of the iron nail dipped in the copper sulphate solution with the one kept aside.

Observation: the iron nail dipped in the copper sulphate solution in test tube A becomes brownish in colour and the blue colour of copper sulphate solution fades in test tube A. While the blue colour of copper sulphate solution in test tube B remains the same. 

Conclusion: iron has displaced or removed another element, copper, from copper sulphate solution in test tube A. This reaction is known as displacement reaction. 

Fe(s)            +       CuSO4(aq)             →       FeSO4(aq)              +       Cu(s)
                        [copper sulphate]                    [Iron sulphate]

Activity 1.10 (Experiment):

Aim: To show double displacement reaction 

Apparatus: 3 ml of sodium sulphate, 2 test tubes, 3 ml of barium chloride solution.
Procedure: Take about 3 ml of sodium sulphate solution in a test tube. In another test tube, take about 3 ml of barium chloride solution, Mix the two solutions. 

Observation: A white substance, which is insoluble in water, is formed. This insoluble substance formed is known as a precipitate. Any reaction that produces a precipitate can be called a precipitation reaction. 

Conclusion: This is a double displacement reaction shown by the equation below where Na+ being more reactive than Ba+2 displaces Ba+2 from its compound BaCl2 and takes its place to form NaCl.
Na2SO4(aq)          +     BaCl2(aq)                →          BaSO4(s)         +       2NaCl(aq)
(sodium sulphate)        (Barium chloride)                (Barium sulphate)  (Sodium chloride)

Activity 1.11 (Experiment):

Aim: To show oxidation and reduction reaction  

Apparatus: China dish 1g copper powder, burner, wire gauze, tripod stand and Hydrogen gas. 

Procedure:
Heat a china dish containing about 1 g copper powder.
Now pass hydrogen gas over this heated material.

Observation:
The surface of copper powder becomes coated with black copper oxide.
Hydrogen gas is passed over this heated material [CuO] the black coating on the surface turns brown as the reverse reaction takes place and copper is obtained.

Conclusion: In the first case copper, was oxidized to copper oxide by the following reaction
2Cu + O2                       -----Heat→ 2CuO 
this is an oxidation reaction               (black coating)

In the second case when hydrogen gas was passed over heated [CuO] copper metal was obtained because copper oxide got reduced to copper metal by the following reaction 

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