X Board Question Ch: Human Eye and Colourful World

Guess Paper for Board exam 2014

Q. (a) List the factors on which scattering of light depends. (b) What is Tyndals, effect ?

Q. A student sitting on the last bench in a class room cannot read the black board clearly.

(i) Name the kind of defect of vision the student is suffering from.

(ii) Name the type of spherical lens he has to use to correct this defect.

(iii) State two possible reasons for this defect of vision.

Q. Why do stars appear to twinkle while the planets do not ? Explain with the help of diagram.

Q. Explain with the help of diagram why the sun is visible to us two minutes before the actual sun-rise and two minutes after the sunset.

Q. (a) What is meant by power of accommodation of eye ? A person with a defective vision cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision ? Draw a diagram of thus corrected eye. (b) A person having presbyopia uses a bifocal lens to restore proper vision. Which part of the this lens is convex and which part is concave ?

Q. Name the part responsible for the power of accommodation of the human eye.

Q. What is meant by least distance of distinct vision ? How does this vary between the very young and old people ?

Q. Explain why the colour of the clear sky is blue.

Q. State the cause of dispersion, when white light enters a glass prism. Explain with a diagram

Q. What is a rainbow ? When and how is it formed ?

Q. Explain the cause of the red colour of the Sun at Sunrise and Sunset.

Q. List two causes leading to myopia of the eye. Draw ray diagrams to show the image formation in case of defective eye and corrected eye.

Q. We can see the sun for few minutes even after it has actually set. Why ?

Q. A student has difficulty in reading the blackboard while sitting in the last row. What could be the defect of vision the student is suffering from ? What are the causes for this disorder ?

Q. What is meant by power of accommodation of eye ? The minimum power of eye lens is 40D. If the far point of normal eye is infinity find the size of eye ball.

Q. The sky appears dark to the passengers flying at very high attitudes. Why ?

Q. A child has difficulty in reading the blackboard while sitting on the last bench in a class  room. What could be the defect the child is suffering from ? List two main causes of this defect.

Q. State the nature of the image formed at the retina of human eye.

Q. (a) What is the near point of the human eye with normal vision ? (b) Why is a normal eye not able to see clearly the objects placed closer than the near point ?

Q. The sun appears oval (or flattened) at sunrise and sunset, but appears circular at noon. Explain, why ?

Q. A student has difficulty in reading the black board while sitting in the last row

What could be the defect the student is suffering from ? How can it be corrected ? Draw the ray diagrams for (a) defective eye (b) its correction.

Q. State the range of the human eye with a normal vision

Q. Q. “Stars seem higher than they actually are” Explain, why?

Q. What is meant by the power of accommodation of the eye? State the role of ciliary muscles in achieving it.

Q. (a) What is long sightedness? List its causes.  (b) How can it be corrected? Draw the ray diagram for its correction.

Q. Define absolute refractive index of a medium. Light enters from air to water having refractive index 4/3. Find the speed of light in water. The speed of light in vacuum is 3x10⁸ m/s.

Q. With the help of a diagram, explain the formation of a rainbow in the sky.

Q. (i) What is meant by “least distance of distinct vision” ? (ii) How does iris controls the size of the pupil in bright light and dim light ?

Q. A person can see distant sign boards clearly but cannot read clearly a book which is at 25 cm from his eye. Identify the defect. Draw a labelled ray diagram to illustrate how this defect can be corrected.

Q. A person needs a lens of power – 2.5 dioptres for correcting his vision. Name the defect of vision he is suffering from. Which lens will he be using for the correction ? Also find the focal length of the lens. 

Useful study link from:  http://jsuniltutorial.weebly.com/the-human-eye-and-the-colourful-world.html

10th Human eye and Atmospheric refraction Notes

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10th Question from Board Paper (Light – Reflection and Refraction) 2014

 CBSE PHYSICS class 10 Term-II Board Question

 Q. What is the minimum number of rays required for locating the image formed by a convex mirror for an object ? Draw a ray diagram to show the formation of a virtual image by a convex mirror.

Q. A 4.0cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20cm. If the distance of the object from the lens is 30cm, find the position, nature and size of the image. Also, find its magnification.

Q. (a) 4.5cm needle is placed 12cm away from a convex mirror of focal length 15cm. Give the location of the image and the magnification. Describe what happens as the needle is moved farther from the mirror.

(b) What kind of mirror is used in a solar furnace ? Give reason for using this mirror.

 (c) One half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object ? Justify your answer.

Q. (a) When an object is placed at a distance of 60 cm from a convex mirror the magnification produced is 1/2 . Where should the object be placed to get a magnification of 1/3 ? (b) A small electric lamp is placed at the focus of a convex lens. What is the nature of beam of light produced by the lens. Draw a diagram to show this.

Q. The refractive index of a dense flint glass is 1.65 and for alcohol it is 1.36 with respect to air. Find the refractive index of dense flint glass with respect to alcohol.

Q. Draw a ray diagram to show refraction of light through a triangular glass prism and show angle of incidence and angle of deviation.

Q. Refractive index of diamond with respect to glass is 1.6 and absolute refractive index of glass is 1.5. Find (i) absolute refractive index of diamond (ii) Speed of light in diamond. The speed of light in air is 3x10⁸ m/s.

Q. Name a mirror that can give an erect and magnified image of an object. Draw labelled ray diagram to justify your answer.

Q. (a) Define “power of accommodation of eye”.

 (b) A person uses a lens of power -2.0D for correcting his distant vision. For correcting his near vision he uses a lens of power +1.5D. What is the focal length of the lenses required to correct this disorder ?

Q. (a) State Snell’s Law.

 (b) A beam of light passes from air to a substance X. If angle of incidence is 45 degrees and angle of refraction is 30 degrees, calculate the refractive index of substance X. Given sin 30^o = ½ ; sin 45 ^o = 1/rot2  

(c) A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed if the size of the image is equal to the size of the object ? Calculate the power and focal length of the lens.

Q. (a) An object is placed at a distance of 60 cm from a convex mirror the magnification produced is 1/2 . Where should the object be placed to get a magnification of 1/3 ?

 (b) A small electric lamp is placed at the focus of a convex lens. State the nature of beam of light produced by the lens. Draw a diagram to show this.

Q. The radius of curvature of concave mirror is 50cm. Where should an object be placed from the mirror so as to form its image at infinity ? Justify your answer.

Q. (a) Name and define the S.I. unit of power of a lens. (b) How is the power of a lens related to its focal length ? Find the power of a concave lens of focal length 25cm.

Q. (a) State Snell‟s law of refraction. (b) What is the speed of light in a transparent medium which has a refractive index of 1.7 (the speed of light in vacuum is 3x10⁸ m/s)

Q. (a) Two lenses have power of (i) 2D (ii) – 4D. State the nature and focal length of each lens. 

(b) A concave lens has focal length of 20 cm. At what distance from the lens a 5cm tall object be placed so that it forms an image at 15cm from the lens ? Also calculate the size of the image formed.

Q. (a) Name the type of mirror used in the following : 

(i) Headlights of a car. (ii) Rear view mirror of a vehicle. Support your answer with reason.

(b) When an object is placed at a distance of 60cm from a diverging spherical mirror, the magnification produced is 0.5. Where should the object be placed to get a magnification of 1/3  ?

Q. An object is placed at a distance of 20 cm in front of convex mirror of radius of curvature 30 cm. Find the position and nature of the image.

Q. State the type of lens used as a simple magnifying glass. Draw a labelled ray diagram to show the image formation by this lens. List the characteristics of the image formed.

Q. (i) Find the value of the angle of reflection when an incident ray makes an angle of 40^o with a plane mirror.

(ii) Light enters from air into water which has a refractive index of 1.33. Calculate the speed of light in water. (speed of light in air is 3 x 10⁸ m/s.)

Q. Draw a ray diagram in each of the following cases to show the position and nature of the image formed when the object is placed

(i) between pole and principal focus of a concave mirror.

(ii) between centre of curvature and principal focus of a concave mirror.

Name the type of mirror which can be used to obtain a diminished and virtual image of an object. Mention an application of such a mirror . Draw a labelled ray diagram to show the formation of the required image in the mirror.

Q. Name the type of lens that can be used to obtain :

(i) A magnified and virtual image.   (ii) A diminished and virtual image of the object.

Draw labelled ray diagrams to show the formation of the required image in each of the above two cases. Which of these lenses can also form a magnified and real image of the object? Draw labelled ray diagram to show the position of object and image for such a lens.

Q. (i) List any two properties of the image formed by a plane mirror. (ii) The power of a spherical lens is – 2D. State its nature and calculate its focal length in centimeter.

Q. (i) Define optical centre of a lens.

(ii) In refraction of light through a rectangular glass slab, the emergent ray is parallel to the direction of the incident ray. Why ?

(iii) What happens when a light ray is incident normally on one of the faces of a rectangular glass slab ?

Q. (i) Draw a ray diagram in each of the following cases. Also mark the angle of incidence

(i) and angle of reflection in the diagram.

(a) A ray passing through the principal focus of a convex mirror.

(b) A ray incident obliquely to the principal axis towards the pole of a concave mirror. 

(ii) An object, 2.0 cm in size, is placed 20.0cm in front of a concave mirror of focal length 15.0cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image ? Find the nature and the size of the image formed.

Q. (i) Draw the ray diagrams in each of the following cases to show the position and nature of the image formed when the object is placed :

 (a) at „2F‟ of a converging lens. (b) between the focus and optical centre of a converging lens. 

(ii) The magnification produced by a spherical lens is 1/3  . If the image is formed at a distance of 10cm from the lens, find the position of object. Also find the nature and focal length of this lens. 

Q. A 2 cm tall object is placed at a distance of 25 cm from a convex lens of focal length 10 cm. Find the nature, size and position of the image so formed.

Q. With respect to air the refractive index of kerosene is 1.44 and that of diamond is 2.42.  Calculate the refractive index of diamond with respect to kerosene

Q. Name the type of mirror which always forms a virtual and diminished image of the object in front of it. Draw the diagram for the same for an object in front of it at a finite distance. State any one use of it

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CBSE Physics IX Physics Summative II Worksheet – 2011-12

CBSE Physics IX Physics Summative II Worksheet – 2011-12 JSUNIL TUTORIAL,SAMASTIPUR

1 MARK QUESTIONS

1. Nails and pins have pointed tips. Give reasons?

2. State Archimedes’ principle.

3. What will happen to the amount of work done if (a) the magnitude of force applied is increased. (b) the displacement of the body is reduced?

4. What is the work done on a body moving in a circular path?

5. Convert kwh into joules.

6. Why are sound waves called mechanical waves?

7. We cannot hear sound from the space. Why?

8. Why can we recognize our family members from their voice without seeing them?

9. What is meant by echocardiography?

10. What is the audible range of human ear?


2 MARK QUESTIONS

1. What is meant by reverberation? That are the measures taken to reduce reverberation?

2. Distinguish between longitudinal waves and transverse waves?

3. What happens to the kinetic energy of a body if the mass and velocity of the body are doubled?

4. When is the work done by a force in a body said to be negative? Give two examples.

5. A thrust of 200N exerts a pressure of 10Pa on a body. Calculate the area on which the pressure is exerted?

6. What is meant by echo? What are the conditions for the formation of an echo?

7. 8000 J of work is done by a machine to lift a mass of 100kg vertically upwards. Calculate the height to which the mass is lifted?

8. State the essential conditions needed for work to be done?

9. Derive the formula for gravitational potential energy.

10. Give the sequence of energy changes taking place in the production of electricity from a dam ?

3 MARKS QUESTIONS
1. An object of mass 80g has a volume of 20cm3. Will the object float on the water? Why? What will be the mass of water displaced by the object?
2. Give reasons:
a)Balloons filled with hydrogen rise to the ceiling.
b)Tractors have wide tyres.
c)A mug full of water appears light as long as it is under water in the bucket than when it is outside water.
3. State with reason whether work done is positive or negative in the following conditions : 

a) Work done by a man in lifting a bucket out of well by means of a pulley.

b) Work done by losing team in a tug of war.

c) Work done by an applied force on a body moving over a rough horizontal plane with uniform velocity.

d) Work done by a man in lifting a bucket out of well by means of a rope tied to a bucket

e) Work done by gravitational force in above case (d).

f) Work done by gravity on a freely falling object.

4. What kind of energy transformations taking place in the following :

(i)Burning of fuels (ii)Photosynthesis (iii)Arrow released from stretched bows.

5. Define: (i) amplitude (ii) frequency (iii) wave length.

6. What is meant by kinetic energy? Derive an expression for kinetic energy?

7. 50 waves pass through a point in 0.1 second. If the distance between one crest and the adjacent through is 0.34m, calculate frequency, wave length and wave velocity.

8. Represent graphically (a) loud sound and soft sound. (b) high pitch and low pitch sound.  

9. How much will a body of weight 35N weigh in water if it displaces 1 litre of water ?(g = 9.8m/s2)

10. (i) Which wave property determines (a) loudness (b) amplitude? 

5 MARKS QUESTIONS. 

1. a)Define power of a body . State and define the S.I unit of power.

b)Two children A and B both weighing 32kg start climbing up a rope separately and reach a height of 4m. A takes 10s and B takes 15s to reach that level. Calculate the amount of work done by A and B. Which of the two has more power? Show by calculation.

3. a) A body is floating on the surface of a liquid. With the help of a diagram

show the two forces acting on it that are responsible for its floatation.

State the relationship between these two forces in this case?

b)What is relative density? If an object is immersed wholly in a liquid causing up thrust equal to the weight of the body then what will be the relation between the relative densities of liquid and the object?

4. a)State the relation between commercial unit of energy and S.I unit of energy.

b)A man drops a 10kg rock from the top of 5m ladder. What is its K.E when it just touches the ground? What is its potential energy when it is at the top of ladder?

5. a)What is meant by ultrasound?

b)Explain the principle and working of SONAR?

6. State the law of conservation of energy. Illustrate the law by giving the example of a freely falling object.

10th SA – II Worksheet Physics CBSE Board

3 Mark Questions:-

1. What is the quantitative meaning attached to the term’ power of accommodation’ ? Why can’t we see clearly objects that are too close to the eye ? When do you have the least strain on the muscles of a normal eye ?
2. What is (i) cataract (ii) near point (iii) presbyopia.
3. What is the role of (i) ciliary muscle (2) iris (3) pupil (4) eye lens (5) light sensitive cells (6) retina
4. The near point of a hypermetropic person is 75 cm from the eye. What is the power of the lens required to enable him to read clearly a book held at 25 cm from the eye.
5. (i) A student allows a stream of white light passed through a medium of tiny particles. Which colour will get scattered the most ?
(ii) The refractive indices of diamond and rock salt are 2.42 and 1.54 respectively. If the speed of light in diamond is 1.2 X 108 ms-1, find the speed of light in rock salt.
6. (i) Four students observed an image and concluded that it is virtual, enlarged and erect. What is the nature of the reflecting/refracting surface ?
(ii) A convex mirror used on bus has a focal length of 200 cm. If a scooter is located at 100 cm from this mirror, find the position, nature and magnification of the image formed in the mirror.
7. An object 50 cm tall is placed on the principal axis of a convex lens. Its 20cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the total length of the lens.
8. (i) Define refractive index of a medium.
(ii) Draw diagrams to show the path of ray of light when it goes from (a) air to glass (b) water to air.
9. A person is unable to see the objects beyond 2 cm, clearly cause due to which this detect may arise. Draw ray diagrams to show (i) this defect of vision (ii) correction of this detect using appropriate lens.
10. Draw diagrams to show the refraction of yellow coloured light through a (i) rectangular glass slab (ii) a triangular glass prism.
5 Mark Questions:-
 Give reasons for the following.
1. Stars appear to twinkle
2. Sun appear reddish early in the morning
3. Sky appear dark instead of blue to an astronaut
4. Blue colour of sky
5. Danger signal lights are red in colour.
(i) Name the type of mirror used in the following situations (a) Head light of a car (b) rear-view mirror of a vehicle (c) to see a full length image of a tall building. (d) one half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object ? Verify your answer experimentally. Explain your observations.
(i) magnification produced by a lens is – 2. What does this mean.
(ii) (a) Two lenses have power of (i) + 2D (ii) – 4D, what is the nature and total length of each lens ?
(a) An object is kept at a distance of 100 cm from each of above lenses. Calculate the (i) image distance (ii) magnification in each of the two cases.
4. What is meant by dispersion of white light ? Describe the formation of rainbow in the sky with the help of a diagram. In dispersion of white light through prism, which colour deviates most and which colour the least? Why do they deviate differently ?

5. (a) With the help of a ray diagram, show the type of images formed when object is placed at the following positions in front of concave mirror.
(a) Between F and C (b) at F
(b) The radius of curvature of convex mirror, used on a moving automobile is 2.0 m. A truck is coming behind it at a constant distance of 3.5 m. Calculate (i) the position and (ii) the size of image relative to the size of the truck. What will be the nature of the image ?
6. (i) Draw a ray diagram to show passage of a ray of light through a rectangular glass slab, when the angle of incidence is zero.
(ii) what you mean by lateral displacement, Write any two factors on which it depends.
(c )with the help of an activity demonstrate the scattering white light.
7. (a) It is required to get (i) a magnified, erect and virtual image (ii) a diminished, erect and virtual image of a given object. What type of lens should we use in each case and where should the object be kept ?
(b) Draw ray diagrams to show the required image formation in each case.
(c) Which of these lenses could also form a magnified, real and inverted image ? Also indicate the position of the object for which this could happen ?
8. Draw a ray diagram in each case to show the position and nature of the image formed when the object is placed.
(i) at the centre of curvature of a concave mirror.
(ii) between the pole and focus of a concave mirror.
(iii) in front of a convex mirror
(iv) at 2F of a convex lens
(v) in front of a convex lens.
9. A convex lens is being used to get a three-fold magnified image of an object. The lens has a power of + 4.0D. Find the two positions of the object for this magnification and show the image formation in each case through the appropriate ray diagram.

10. A concave mirror produces three times magnified (enlarged) real image of an object 10 cm infront of it. Where is the image located ?

CBSE Science and Technology Class: X Assignments 2012

CBSE Science and Technology Class: X Assignments 2012

Chapter: CABBON and ITS COMPOUNDS

1.Write the molecular formula of ethanol.

2.An organic compound X having molecular formula C₂H₄O₂, gives brisk effervescence with sodium bicarbonate. Give the formula and the name of X.

3 The general formula of a homologous series of carbon compounds is C_nH_2n+1OH.Write the molecular formulae of fourth and fifth members of this series?

4.Illustrate the IUPAC system of nomenclature for the following compounds:

    (a).CH₃OH        (b).C₂H₈OH           (c ).C₃H₇OH.

5.What happens when a dry piece of sodium metal is added to ethyl alcohol?

Explain with equation.

6.What happens when ethyl alcohol is warmed with alkaline potassium permagnate?

7.What will be the formula and electron dot structure of Propyne?

8.Write chemical equation for saponification & esterification.

9.The molecular formula C₃H₆O can represent an aldehyde as well as a ketone.

Write their structure and name them.

10.Why should one condemn drinking of alcohol?

11.Define isomerism.

12.How is that we can use  detergents not soaps for washing clothes even when water is hard?

Assignment Subject: Class: X Chapter: Periodic Classification of Elements

1. How many elements were discovered at the time of Mendeleev?

1. Define Atomic radius and give its variation along group and period.

1. Three elements A, B and C having atomic radii 124pm, 456pm and 324pm respectively. Arrange them according to their position in group.

1. Which law was based on the notes of music?

1. State Modern periodic law.

1.  What was the main advantage of Mendleev’s periodic table?

1. What are metalloids? Explain about their position in Modern periodic table.

1. Why was it necessary to change the basis of classification from atomic weight to atomic number?

1. Two elements having atomic no.12 and 17 both belong to same period. State reason.

1. Explain how Modern periodic law was able to tell about the position of isotopes in periodic table, which cannot be explained by Mendeleev?

1. (a) State two defects of Modern periodic table.

1. What are the units of inheritance in living organisms? Where are they located?

1. Name the theory of evolution given by Charles Darwin & name the book in which it was given?                                              

1. Define Genetics. What was the contribution of Mendel in this branch of biology?

1. How do embryological studies provide evidence in favor of evolution?

1. How is artificial selection beneficial?

1. How analogous organs provide evidence in favor evolution?

1. Explain diagrammatically Mendels MONOHYBRID & DIHYBRID CROSS?

1. Humans have evolved in a tree like structure. Discuss.

1. A cross between round and wrinkled seeds produced round seeds. When these were selfed out 420 seeds 300 were round &102 were wrinkled.

1. A species give rise to new species with a complex body design. Will be better than the old species.

1. A ray of light incident normally on a mirror retraces its path. Why?

1. State mirror formula. Will focal length of mirror changes on changing the distance of the object? If not, why? What determines the focal length of the mirror?

1. What kind of lens is there in human eye? What enables the eye to focus objects at different distances?

1. Explain: a) Sun appears to rise 2 minutes before and sets 2 minutes later.What is meant by persistance of vision?

1. b) Sky appears blue.

1. c) Stars twinkle at night

1. What is meant by myopia and hypermetropia? How can the two be corrected? Explain with the help of diagram?
2. A person cannot see the object distinctly hen placed at a distance less than 100 cm. What is the power of spectacles that he should use to see clearly the objects placed at 25 cm?
3. A 14-year-old student is not able to see clearly the questions written on the blackboard placed at a distance of 5m from him (a) Name the defect of vision he is suffering from. (b) With the help of labeled ray diagrams show how this defect can be corrected (c) Name the type of lens used to correct the defect.
4. What is presbyopia? What causes presbyopia? How it can be corrected?

5. Why we are not able to see immediately after we enter a darkened hall?

(b) The atomic number of X, Y and Z are 9, 11 and 17.

i.) Which of them belong to the same group?

ii.) Which of them belong to the same period?

iii.) Which is bigger in size: X or Z and why?

12. (a) Give reason:

i). A chlorine atom is smaller than a sodium atom although atomic number of chlorine (11) is greater than sodium (17).

ii.) All elements of the same group have similar properties.

iii.) the noble gases are placed in separate group.

(b) An element X belongs to third period and group 16 of the periodic table.

i)    Write its electronic configuration and name.

ii)   What is the valency of X?

Class: X Chapter: HOW DO ORGANISMS REPRODUCE

1.What is the basic difference between asexual and sexual reproduction?

2.Which of the following organisms reproduce by asexual method? Amoeba, Cat, Birds, Hydra.

3Name one organism, each which reproduces by:

 a. Binary fission     b Spore formation        c. Budding      d. Fragmentation

4. Where are  male and female gametes formed in:

a. Human beings               b. flowering plants.

5. What is vegetative propagation? Give its two advantages.

6. Differentiate between unisexual and hermophrodite organisms.

7. Define fertilization. Where does fertilization take place in human body?

8. What are STD`s? Give 2 examples.

9. Draw labeled diagram of:  A) Human male reproduction system   b) Human female reproduction system 

10. What are male and female gonads in human beings?

11. What is pollination? Explain the 2 types of pollination.

12. Explain the structure of flower with the help of a labeled diagram.

13. Define the terms~

                a) Gestation period        b) Implantation     c) Placenta    

14. Describe the function of surgical method of birth control.

15. What is the full form of OCs? Which substances are contained in these? How do they work? 

Assignment Subject: Science and Technology Class: X Chapter: Heredity and Evolution

Assignment PHYSICS Class: X Chapter: : LIGHT: REFLECTION AND REFRACTION

3. A thin lens has a focal length of –25 cm. What is the power of the lens? Is it convex or concave?

4. A converging mirror form a real image of height 4 cm, of an object of height 1 cm placed 20 cm away from the mirror. Calculate the image distance. What is the focal length of the mirror?

5. An arrow 2.5 cm high is placed at a distance of 25 cm from a diverging mirror of focal length 20 cm. Find the nature, position and size of the image formed.

6. A pond of depth 20 cm is filled with water of refractive index 4/3. Calculate apparent depth of the tank when viewed normally.

7.Calculate the distance at which an object should be placed in front of a thin convex lens of focal length 10 cm to obtain a virtual image of double its size.

8. A concave lens of focal length 25 cm and a convex lens of focal length 20 cm are placed in contact with each other. What is the power of this combination? Also calculate focal length of this combination

Assignment Subject: Science and Technology Class: X Chapter: Our Environment

1.Which of the following materials are biodegradable? Aluminium wire, Tea leaves, Synthetic fibre and wool.

2 Arrange the following in a food chain: Fish, Algae, Small animals and Big fish.

3.Define tropic level. Draw the food chain with four tropic level.

4.In a food chain consisting of grass, frog, bird and insects, where will the concentration of the harmful chemical be maximum?

5.What is meant by bioconcentration of pestisides? Which common pestisides has accumulated in human body in considerable amounts?

6.If we use excess pestisides to protect the crops from diseases,then it may cause long term damage to mankind.Justify the statement.

7.What is the difference between food chain food web?Give suitable examples. Explain how harmful chemicals enter our bodies.

8.What is ozone and how does it affect any ecosystem?

9. Write a note on the flow of energy through different steps in the food chain.

10.Consider the food chain: Grass-Goat-Tiger.

If tiger has 30 J of energy available in this food chain, how much energy was originally available in grass?

11.What is 10%law? Explain with an example how energy flows through different tropic levels.

Assignment Subject:Class: X Chapter: Management of Natural Resources

1.Name the three R’s to save the environment. Explain each of them.

2.What is ‘Amrita Devi Bishnoi National Award’?

3.Explain the role of forests in conserving the environment. How do forests get depleted? What are its consequences?

4.What is Narmada Bachao Andolan?

5.What are the advantages of building dams?

6.How do you achieve sustainable development?

7.How is Khejari tree related to the preservation of biodiversity?

8.How do we find contamination of water?

9.How is conservation indifferent from preservation?

10.How does socio-cultural environment affect human beings?

11.Name any two wastes that can be recycled and reused.

12.How can you as an individual contribute or make a difference to the management of:

      (a) forests and wild life.            (b)water resources       (c)coal and petroleum?