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?

class 10 MAGNETIC EFFECTS OF CURRENT(Assignment)

CBSE PHYSICS  TYPE  A MAGNETIC FIELD and  FIELD LINES

1. What effects do you expect on passing current through a conductor?
2. How it can be shown that a current carrying conductor produces a magnetic field?
3. Why compass always align itself in approximately north–south direction?
4. Why some substances exhibit magnetism naturally, while others don’t?
5. What do you mean by ‘magnetic field lines’?
6. List the characteristics of magnetic field lines?
7. How magnetic field lines are drawn?
8. How one can represent a region of uniform magnetic field using magnetic field lines?
9. Why two magnetic field lines never cross each other?
10. What is the direction of magnetic field line?
11. What is necessary to have a magnetic field?
12. What do you mean by magnetic field?
13. If equal number of electrons and proton travels in same direction, will there be any magnetic field
produced?
14. Is it possible that magnetic field line emerging out of north pole of one bar magnet can enter the south pole of another bar magnet?
15. Can magnetic field lines of two different bar magnets cross each other on bringing the bar magnets closer?
16. Consider that there is a long queue of electrons at rest. Will you experience any magnetic field moving along this queue of electrons?
17. Can we separate north pole and south pole of a magnet?
18. What will happen if we break a bar magnet into two equal halves?

19. Magnetic fields in two different regions described by magnetic field lines as shown below.

What conclusion one can draw about the magnetic fields in region 1 and 2?

20. Detect the north pole of the bar magnet, show below?

TYPE B MAGNETIC FIELD DUE TO CURRENT CARRYING CONDUCTOR

1. Show the magnetic field pattern produced due to a straight current carrying conductor.
2. Which rule can help us to find the direction of magnetic field lines around a straight current carrying conductor?
3. What factors influence the magnetic field around a current carrying conductor?
4. What is a solenoid? How will you increase the magnetic field strength due to solenoid?
5. Show the magnetic field pattern produced due to current carrying circular loop and solenoid.
6. What is an electromagnet?
7. What is the difference between the magnetic field pattern of a solenoid and a bar magnet?
8. What you can say about magnetic field inside a solenoid?
9. When we can use right hand thumb rule?
10. Magnetic field at the center of a current carrying loop (in the plane of paper) is directed in the outward direction. What will be the direction of the current flow?
11. What are electromagnets? Discuss their advantages over natural magnets.
12. A current is flowing vertically upward in a wire. What will be direction of field lines if
(a) wire is in front of you? (b) wire is at your backside?
13. In the figure given below, find the direction of the current in the wire.

14. Can we change the pattern of magnetic field around a current carrying conductor? If yes then how?
15. What will happen to magnetic field strength of a current carrying solenoid if we increase the number of loops?
16. Can magnetic field line be parallel to the direction of current flow?
17. Where is the region of uniform magnetic field due to a current carrying solenoid?
18. Can there be a magnetic field without flow of charge (current)?

TYPE C MAGNETIC FORCE AND ELECTRIC MOTOR

1. On what factors, does the force experienced by a current carrying conductor placed inside a magnetic field, depends?
2. How one can show experimentally that force on a current carrying conductor depends upon the
(a) direction of the magnetic field? (b) direction of the flow of current?
3. Why is current carrying conductor experiences a force on placing it, inside a magnetic field?
4. When the force experienced by a straight current carrying conductor will be maximum?
5. How one can determine the direction of force on a straight current carrying conductor placed inside a magnetic field?
6. Can the magnetic force, on a charge moving in magnetic field, accelerate the charge linearly?
7. In which direction, does the electron beam moving along the earth’s equator (from west to east) will experience the force due to the earth’s magnetic field?
8. State the principle on which an electric motor works.
9. Name the device which converts electrical energy into mechanical energy?
9. Explain the working of an electric motor with the help of a labeled diagram.
10. What is the function of split rings in an electric motor?
11. How rotation of electric motor armature will be affected on (i) interchanging the magnetic poles (ii) reversing battery polarity (iii) both (i) and (ii) simultaneously?
12. Can direction of flow of current, direction of magnetic field and magnetic force on that current carrying conductor lie in same plane?

13. A bar magnet is placed inside a uniform magnetic field as shown below.

14. What type of motion do you expect from the bar magnet?
15. What will happen if we change the split ring by two different complete rings in an electric motor?
16. What will happen if we use circular coil instead of rectangular coil in armature of an electric generator?
17. Can we differentiate magnetic field lines formed due to a bar magnet and a current carrying solenoid using a compass?
18. If a current carrying conductor experiences a force (action) on placing it in a magnetic field then which component experiences its reaction as per the Newton’s third law?
19. If we halve the number of turns in a current carrying solenoid without changing anything else, what will be the difference in force experienced on placing it in a magnetic field from the previous case?
20. What will happen to the rotation of armature if we:–
(a) increase the number of rectangular turns? (b) increase the magnetic pole strength?
(c) decrease the current through armature coil?

TYPE_ D ELECTROMAGNETIC INDUCTION AND ELECTRIC GENERATOR

1. Explain the working of a galvanometer?
2. What is electromagnetic induction? Design an experiment to describe this phenomenon.
3. By how many different means one can induce current in a conductor?
4. What do you mean by A.C. (Alternating Current)?
5. State the principle on which electric generator works.
6. Explain the working of an electric generator using a labeled diagram.
7. If a bar magnet is moving with a constant speed with respect to a solenoid connected to a galvanometer. What do you expect to observe?
8. What is the difference between an A.C. and a D.C. electric generator?
9. How and by whom electromagnetic induction was discovered?
10. State Fleming’s right hand rule. Name a device which works on this principle.
11. Why electromagnetic induction is termed so?
12. What is necessary to induce a current in a conductor?
13. What will happen to the output current of a D.C. generator if we:–
(a) increase the number of turns in armature coil?
(b) increase the magnetic pole strength?
(c) decrease the speed of rotation of armature coil?
(d) replace the split rings with two different complete rings attached to either end of armature coil?
14. Draw a labeled diagram showing rotational motion of a rectangular coil inside a magnetic field and
direction of induced current.
15. How one can show experimentally that electricity and magnetism are linked?
16. A solenoid is placed in the neighborhood of a strong electromagnet. Will there be any induced current?

TYPE_ E DOMESTIC ELECTRICAL CIRCUITS

1. What type of load combination (parallel or series) is usually followed in domestic electrical circuits and why?
2. Why earthing is done in an electrical circuit?
3. Briefly discuss the power distribution to a household circuitry.
4. What is the function of a fuse in an electrical circuit? What special characteristics should it possesses?
5. List the advantages of using fuse in an electrical circuit.
6. What colour scheme is generally used for the power wires?
7. What are the general specifications of electrical power we receive from the electricity board?
8. What is the difference between direct current and alternating current?
9. What do you mean by overloading of an electric circuit?
10. What precautions one should take to avoid overloading?
11. How fuse prevents damage during overloading or a short circuit?
12. What happens during a short circuit?
13. Can overloading in parallel combination can be taken equivalent to a short circuit?

QUESTION BANK Class X Physics (Electricity)

CBSE PHYSICS  QUESTION BANK Class X Physics (Electricity)

Very short answer questions (1 mark) 

1. Give the unit of (a) Charge (b) Current

2. Define current

3. Name the unit of (a) electrical resistance (b) resistivity

4. Define One Ohm

5. Define Resistivity

6. What is the resistance of a torch bulb rated at 2.5 V and 500 mA?

7. Two resistances of each 2 ohm are connected in parallel. Find their equalent resistance.

8. On what factors does the resistivity of a material depend?

9. Plot a graph between the Potential difference V and current I through a conductor 

10. What happens to the resistance of the circuit if the current through it is doubled?

Short answer questions (2 marks)

1. Two wires of same material are having length L and 2L. Compare their resistance and resistivity.

2. Why are coils of electric toaster and electric iron made of an alloy rather then a pure metal?

3. Two wires are of same length and radius but one of them is copper and the other is of iron. Which will have more resistance? (Given the resistivity of copper = 1.62 x 10 -8 ohm meter and resistivity of iron = 10 x 10-8 ohm meter.

4. Define 1KWh. Give the relation between 1kwh and Joule.

5. State which has a higher resistance. A 50W or 25W lamp. Also find the ratio of their resistances.

6. A wire of resistance 5 Ohm is spent in the form of closed circle. What is the resistance between 2 points at the ends of any diameter of the circle?

7. Calculate the amount of charge that would flow in one hour through the element of an electric irondrawing a current of 0.4 amps.

8. A electric toaster of resistance 20 Ohm takes a current of 5A. Calculate the heat developed in 30 s.

9. A bulb is rated at 5V, 100mA. Calculate its (1) Power (2) Resistance

10. Name two special characteristics of a heater coil.

Short answer questions (3 marks)

1. Define resistance and resistivity. Give the relation between them. Explain the dependence of resistance on temperature.

2. With the help of neat circuit, derive the expression for the equalent resistance of 3 resistances connected in series.

3. With the help of neat circuit, derive the expression for the equivalent resistance of 3 resistances connected in parallel

4. (a ) Draw the circuit consisting of a battery of five 2V cells, 5ohm resistor, 10 ohm resistor, 15 ohm resistor and a plug key. All connected in series (b) Calculate the current passing through the above circuit when key is closed.

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