CLASS XII-A SUBJECT: - PHYSICS - … · SUMMER HOLIDAYS HOME-WORK CLASS – XII-A SUBJECT: -...

SUMMER HOLIDAYS HOME-WORK

CLASS XII-A

SUBJECT: - PHYSICS

ELECTROSTATICS

1. Two electrically charged particles, having charges of different magnitude, when placed at a distanced from each other, experience a force of attraction F. These two particles are put in contact and again placed at the same distance from each other. What is the nature of new force between them? Is the magnitude of the force of interaction between them now more or less than F? (Marks-1)

2. Find the amount of work done in rotating an electric dipole, of dipole moment 3x10-8 Cm, from its position of stable equilibrium, to the position of unstable equilibrium, in a uniform electric field of intensity 104 N/C (Marks-2)

3. State the principle of a machine that can build up high voltages of the order of a few million volts. Also explain the construction and working of this machine. (Marks-5) Or

Three identical parallel plate (air) capacitors C1, C2 C3 have capacitances C each. The between

their platesis now filled with dielectrics as shown. If all the three capacitors, still equal

capacitances, obtain the relation between the dielectric constants K, K1, K2, K3

4. Charges of magnitudes 2Q & - Q are located at points (a, o, o) and (4a, o, o). Find the ratio of the flux of electric field, due to these charges, through concentric spheres of radii 2a and 8a centered at the origin.(Marks-1)

5. Find the amount of work done in arranging the three point charges, on the vertices of an equilateral triangle, ABC, of side 10cm, as shown in the figure.(Marks-2)

6. Find the expression for the electric field intensity, and the electric potential, due to a dipole at a point on the equatorial line. Would the electric field be necessarily zero at a point where the electric potential is zero? Give an example to illustrate your answer.(Marks-5) OR

Find the expression for the capacitance of a parallel plate capacitor of area A and plate

separation d if (I) a dielectric slab of thickness t, and (ii) a metallic slab of thickness t, where


(t


(i) Identify the charge distribution and justify your answer. (ii)

if the potential due to this charge distribution has a value V at the point A, what is its value at

the point A?(Marks-3)

12. A charge Q located at a point is in equilibrium under the combined electric field of three charges q1. q2, q3. If the charges q1, q2 are located at points r1 and r2 respectively, find the direction of the force on Q, due to q3 in terms of q1,q2, r1, r2,and r (Marks-3)

13. What is the angle between the directions of electric field at any (i) axial point and (ii) equatorial point due to an electric dipole? (Marks-1)

14. Four point charges are placed at the four corners of a square in the two ways (i) and (ii) as shown below

Will the (1) electric field (ii) electric potential, at the centre of the square, be the same or

different in the two configurations and why? (Marks-2)

15. Two identical plane metallic surfaces A and B are kept parallel to each other in air separated by a distance of 10 cm as shown in the figure.

Surface A is given a positive potential of 10 V and the outer surface of B is earthed. (i) What is

the magnitude and direction of the uniform electric field between points Y and Z? (ii) What is

the work done in moving a charge of 20 C from point X and point Y? (Marks-2)

16. An electric dipole of dipole moment P is placed in a uniform electric field. Write the expression for the torque E experienced by the dipole. Identify two pairs of perpendicular vectors in the expression. Show diagrammatically the orientation of the dipole in the field for which the torque is (I) Maximum (ii) half the maximum value (iii) Zero. (Marks-3) OR


Two capacitors with capacity C1 and C2 are charged to potential V1 and V2 respectively and then

connected in parallel. Calculate the common potential across the combination, the charge on

each capacitor, the electrostatic energy stored in the system and the change in the

electrostatic energy from its initial value.

17. The graph shown here, shows the variation of the total energy (E) stored in a capacitor against the value of the Capacitance(C) itself. Which of the two - the charge on the capacitor or the potential used to charge it is kept constant for this graph? (Marks-1)

18. The two graphs drawn below, show the variation of electrostatic potential (V) withr

1 (r being

distance of the field point from the point charge) for two point charges q1 and q2. (i) What are the signs of the two charges?

19. (ii) Which of the two charges has a larger magnitude and why?

20. A point charge Q is placed at point 0 as shown in the figure. Is the potential difference VA VB positive, negative or zero, if Q is (1) positive (ii) negative?(1)

21. Two uniformly large parallel thin plates having charge densities + and are kept in the X-Z plane at a distanced apart. Sketch an equipotential surface due to electric field between the plates. If a particle of mass m and charge -q remains stationary between the plates, what is the magnitude and direction of this field? OR

Two small identical electrical dipoles AB and CD, each of dipole moment p are kept at an

angle of 1200 as shown in the figure. What is the resultant dipole moment?of this

combination? If this system is subjected to electric field (E) directed along + X direction, what

will be the magnitude and direction of the torque acting on this?


22. Figure shows two identical capacitors, C1 and C2, each of 1 F capacitance connected to a battery of 6 V. Initially switch S is closed. After sometime S is left open and dielectric slabs of dielectric constant K = 3 are inserted to fill completely the space between the plates of the two capacitors. How will the (i) charge and (ii) potential difference between the plates of the capacitors be affected after the slabs are inserted? ?(2)

23. Using Gausss laws obtain the expression for the electric field due to a uniformly charged thin spherical shell of radius R at a point outside the shell. Draw a graph showing the variation of electric field with r, for r> R and r < R.(3)

24. The two graphs drawn below, show the variation of electrostatic potential (V) with 1/r (r being distance of the field point from the point charge) for two point charges q1 and q2.

(i) What are the signs of the two charges? (ii) Which of the two charges has a larger magnitude

and why? (1)

25. Obtain an expression for the capacitance of a parallel plate (air) capacitor. The given figure shows a network of five capacitors connected to a 100V supply. Calculate the total charge and energy stored in the network.


OR

Use Gausss law to obtain an expression for the electric field due to an infinitely long straight

Uniformly charged wire,Electric field in the above figure is directed along + X direction and

given

By E = 5Ax + 2B, where E is in N/C an x is in meter, A and B are constants with dimensions.

Taking A = 10 N/CM and B 5 N/C. Calculate (i) the electric flux through the cube.(ii) net charge

enclosed within the cube (3)

.

26. In which orientation, a dipole placed in a uniform electric field is in (1) stable, (ii) unstable equilibrium?(1)

27. Figure shows three charges +2q, - q and +3q. Two charges +2 q and -q are enclosed within surface S. What is the electric flux due to this configuration through the surface S?(1)

28. A parallel plate capacitor is charged by a battery. After some time the battery is disconnected and a dielectric slab with its thickness equal to the plate separation is inserted between the plates. How will (i) the capacitance of the capacitor, (ii) potential difference between the plates and (iii) the energy stored in the capacitor be affected? Justify your answer in each case. (3)

29. (a) Depict the equipotential surfaces for a system of two identical positive point charges placed a distance d apart.(b) Deduce the expression for the potential energy of a system of two point charges q1 andq2brought from infinity to the points r1andr2 respectively in the presence of external electric field E.(3)

30. A parallel plate capacitor, eth with plate area A and separation d, is charged to a potential difference V. The battery used to charge it remains connected. A dielectric slab of thickness d and dielectric constant k is now placed between the plates. What change, if any, will take place in :(i) charge on plates?(ii) electric field intensity between the plates?(iii) capacitance of the capacitor. Justify your answer in each case. .(3)

31. Name the physical quantity whose S.I. unit is J/C. Is it a scalar or a vector quantity?(10M-O-1-1) 32. A spherical conducting shell of inner radius and outer radius i has a charge Q. A charge q is

placed at the centre of the shell.(a) What is the surface charge density on the (i) inner surface,


(ii) outer surface of the shell?(b) Write the expression for the electric field at a point x > r2 from the centre of the shell. ?(2)

33. Show that the electric field at the surface of a charged conductor is given by E =/2 where is the surface charge density and h is a unit vector normal to the surface in the outward direction. (2)

34. A network of four capacitors each of 12 F capacitance is connected to a 500 V supply as shown in the figure. Determine (a) equivalent capacitance of the network and (b) charge on each capacitor.(2)

35. (i) Can two equi-potential surfaces intersect each other? Give reasons. (ii) Two charges q and +q are located at points A (0, 0, -a) and B (0, 0, +a) respectively. How

much work is done in moving a test charge from point P (7, 0, 0) to Q (-3, 0, 0)? (2)

36. Three identical capacitors C1, C2 and C3 of capacitance 6F each are connected to a 12 V battery as shown.C3Find (i) charge on each capacitor(ii) equivalent capacitance of the network (iii) energy stored in the network of capacitors(3)

37. A thin conducting spherical shell of radius R has charge Q spread uniformly over its surface. Using Gausss law, derive an expression for an electric field at a point outside the shell. Draw a graph of electric field E(r) with distance r from the centre of the shell for 0 r (3)

38. A 500 C charge is at the centre of a square of side 10 cm. Find the work done in moving a charge of 10 C between two diagonally opposite points on the square.(1)

39. Derive the expression for the electric potential at any point along the axial line of an electric dipole? (2)

40. (a) Using Gausss law, derive an expression for the electric field intensity at any point outside a uniformly charged thin spherical shell of radius R and charge density a C/m2. Draw the field lines when the charge density of the sphere is (I) positive, (ii) negative. (b) A uniformly charged conducting sphere of 2.5 m in diameter has a surface charge density

of 100 C/m2. Calculate the (i) charge on the sphere (ii) total electric flux passing through the

sphere

Or

(a) Derive an expression for the torque experienced by an electric dipole kept in a uniform

electric field.

(b) Calculate the work done to dissociate the system of three charges placed on the vertices of

a triangle


as shown. Here q= 1.6 x 10-10C.

41. The electric field E due to a point charge at any point near it is defined as E = lim0

where q is

the testcharge and F is the force acting on it. What is the physical significance of lim q0 in this expression? Draw the electric field lines of a point charge Q when (i) Q > 0 and (ii) Q < 0

OR

Define electric flux. Write its SI. Units. A spherical rubber balloon carries a charge that is

uniformly distributed over its surface. As the balloon is blown up and increases in size, how

does the total electric

flux coming out of the surface change? Give reason(2)

42. Deduce an expression for the electric potential due to an electric dipole at any point on its axis. Mention one contrasting feature of electric potential of a dipole at a point as compared to that due to a single charge. (3)

43. A parallel plate capacitor, each with plate area A and separation d, is charged to a potential difference V.The battery used to charge it is then disconnected. A dielectric slab of thickness d and dielectric constantK is now placed between the plates. What change, if any, will take place in (i) charge on the plates (ii) electric field intensity between the plates (iii) capacitance of the capacitor. Justify your answer in each case. (

44. Two point charges 4C and -2 C are separated by a distance of 1 m in air. Calculate at what point on the line joining the two charges is the electric potential zero. (2

45. State Gausss theorem in electrostatics. Apply this theorem to derive an expression for electric field intensity at a point near an infinitely long straight charged wire.(3)

46. Explain the underlying principle of working of a parallel plate capacitor. If two similar plates, each of area A having surface charge densities + and are separated by a distance d in air, write expressions for (i) the electric field at points between the two plates.(ii) the potential difference between the plates.(iii) the capacitance of the capacitor so formed. (3)

47. Explain the principle of a device that can build up high voltages of the order of a few millioiiVo1ts.Draw a schematic diagram and explain the working of this device. Is there any restriction on the upper limit of the high voltages set up in this machine? Explain.

48. Draw a plot showing the variation of (i) electric field (E) and (ii) electric potential (V) with distance r due to a point charge

49. (a) Define electric flux. Write its S.I. units. (b) Using Gausss law, prove that the electric field at a point due to a uniformly charged infinite plane sheet is independent of the distance from it.(c) How is the field directed if (i) the sheet is positively charged, (ii) negatively charged?

50. Why should electrostatic field be zero inside a conductor?

NOTE:- All question of NCERT of First Unit Electrostatics.


English

1. Read The Enemy and write a comprehensive summary.

2. Write articles on the following topics:

a. Role of Technology in eradicating Corruption

b. Farmer Suicides--- Malady & Remedy

c. Talent Hunt ShowsBlessing or Curse?

3. Write speeches on the following topics:

a. Need for Civic Sense

b. Growing Intolerance in India

c. Mobile phonea necessary evil

4. Write in favor or against the following motions:

a. There should be no holiday on the birth anniversaries of Great persons

b. Govt is responsible for farmer suicides

c. Politicians are the most corrupt people in India

5. Read chapter 1-10 of The Invisible Man and write a brief summary of each along with two

long answer questions & their answers.

MATHEMATICS

1. Do the previous years board question of following chapters

Relation and Function

(SAQ 2,3,6,9,10,13,19 AND LAQ 1, 4, 5, 20)

Inverse trigonometric function

(SAQ1,7,13,16,22,24,29,30,32,33,38,48,52)

Matrices

(SAQ 1,3,4,12,14,15,17,18,19,23,25,30,34)

Determinants

(SAQ 1,2,3,8,13,19,22,28,36,45,50,51)

(Sheets already given)

2. Do the miscellaneous exercise of following chapters

Relation and function(Q No. 1,4,9,10,12,15)

Inverse Trigonometric function(Q No.8, 10, 11, 13, 16)

Matrices(Q No. 2,4,6,9,10,11,12)

Determinants(Q No. 4,11,12,14,15,17)


HOLIDAY HOME WORK (SUMMER VACATION) By Dr M S MEENA (PGT Chemistry)

SUB- CHEMISTRY CLASS-XII A (From Unit No. 1 To 3) &Individual investigatory project

Instruction-

Answer the following questions as per your class roll numbers UNIT-1 SOLID STATE

For those students whose roll numbers are

1,3,5,7,9,11,13,15,17,19,21,23,25,27,29

1. Which point defect lowers the density of a crystal?

2. Some of the very old glass objects appear slightly milky instead of being transparent why?

3. What is anisotropy?

4. What is the coordination number of atoms?

a) in fcc structure b) in bcc structure 5. What are the co-ordination numbers of octahedral voids and tetrahedral voids?

6. Why common salt is sometimes yellow instead of being of being pure white?

7. A compound is formed by two elements X and Y. The element Y forms ccp and atoms of X

occupy octahedral voids. What is formula of the compound?

8. What do you mean by paramagnetic substance?

9. Which substance exhibit schottky and Frenkel both defects.

10. Name a salt which is added to Agcl so as to produce cation vacancies.

11. Why Frenkel defects not found in pure Alkali metal halide.

12. What is the use of amorphous silica?

13. Analysis shows that a metal oxide has the empirical formula Mo.9801.00. Calculate the

percentage of M2+ and M3+ ions in the crystal.

14. What is the co-ordination no. of cation in Antifluorite structure?

15. What is the Co.No.of cation and anion in Caesium Chloride.

16. What is F centre?

Sub.- CHEMISTRY CLASS-XII A (From Unit No. 1 To 3) &Individual investigatory project


2,4,6,8,10,12,14,16,18,20,22,24,26,28,30 AND 31


17. Explain how electrical neutrality is maintained in compounds showing Frenkel and

Schottky defect. 18. Calculate the number of atoms in a cubic unit cell having one atom on each corner

and two atoms on each body diagonal. 19. Gold crystallizes in an FCC unit cell. What is the length of a side of the

cell(r=0.144mm) 20. Classify each of the following as either a p-type or n-type semi-conductor.

a) Ge doped with In b) B doped with Si

21. In terms of band theory what is the difference between a conductor, an insulator and a semi-conductor?

22. CaCl2 will introduce Scotty defect if added to AgCl crystal. Explain 23. The electrical conductivity of a metal decreases with rise in temperature while that

of a semi-conductor increases. Explain. 24. What type of substances would make better permanent magnets, ferromagnetic or

ferromagnetic, why? 25. In a crystalline solid, the atoms A and B are arranged as follows:-

a. Atoms A are arranged in ccp array. b. Atoms B occupy all the octahedral voids and half of the tetrahedral voids.

What is the formula of the compound? 26. In compound atoms of element Y forms ccp lattice and those of element X occupy

2/3rdof tetrahedral voids. What is the formula of the compound? 27. The density of chromium is 7.2g cm-3.If the unit cell is a cubic with length of 289pm,

determine the type of unit cell (Atomic mass of Cr=52 u and NA =6.022*1023 atoms mol-1).

28. An element has a bcc structure with a cell edge of 288 pm. The density of the metal is 7.2 g cm3. How many atoms and unit cells are there in 208g of the element

Unit-2 SOLUTIONS


2,4,6,8,10,12,14,16,18,20,22,24,26,28,30 AND 31

1. Carbon tetra chloride and water are immiscible whereas ethanol and water are missible in all proportions .WHY?

2. Why molality is preferred over molarity? 3. 10 gm. of glucose is dissolved in 90 gm of water. Calculate the mass

percentage of glucose.

4. Why solutions deviate from their ideal behavior? 5. Which types of solutions obey Raoultslaw. 6. Why some time we get abnormal molar mass using colligative properties? 7. What is value of van,t Hoff factor for (a) sodium sulphate (b) K4[Fe(CN)6]?

8. Calculate the molality and molarity of 98% sulphuric acid if its density is 1.85

gm/cm3.



Note- For those students whose roll numbers are

1,3,5,7,9,11,13,15,17,19,21,23,25,27,29

9. Why do gases always tend to be less soluble in liquids as the

temperature is raised?

10. Based on solute-solvent interactions, arrange the following in

order of increasing solubility in n-octane and explain.

Cyclohexane, KCI, CH3OH, CH3CN

11. A solution is obtained by mixing 300 g of 25% solution and 400 g of 40% solution by mass. Calculate the mass percentage of the resulting solution.

12. .(a) Calculate the amount of NaCl which must be added to 100 g water so that freezing

point is depressed by 2K. Given that kf for water is 1.86 K/m.

(b) Explain Raoults for solutions containing volatile solute.

(c) What is the Vant Hoffs factor for a solute which undergoes tetramerization?

UNIT-3 ELECTROCHEMISTRY


1,3,5,7,9,11,13,15,17,19,21,23,25,27,29

1. Give the relationship between free energy change and EMF of a cell.

2. Write the relationship between molar conductivity & specific conductivity

3. What is the reference electrode in determining the standard electrode potential?

4. Write the use of platinum foil in the hydrogen electrode.

5. Which electrolyte is used in a dry cell?

6. Name the metal that can be used in cathodic protection of iron against rusting.

7. Why a dry cell becomes dead after some time even it has not been used?

8. Which cells were used in the Apollo space program?

9. How can you increase the reduction potential of an electrode?

10. Which electrolyte is used in mercury cell and fuel cell?

Note- For those students whose roll numbers are

2,4,6,8,10,12,14,16,18,20,22,24,26,28,30 AND 31

11. What are the units of molar conductivity?

12. Define Kohlrauschs law. Calculate limiting molar conductivity of AxBy.


13. When 3 ampere of electricity is passed for 45 minutes 2.0 g of metal is deposited.

Find equivalent weight of metal.

14. Find the value of equilibrium constant from the following data-

15. Calculate standard free energy change for the following chemical reaction

16. Calculate mass of copper deposited when a current of 0.3 ampere is passed in aq

solution of copper sulphate for two hour.

17. Define and give one example of each of the following-

(i) Primary Cells (ii) Secondary Cells (iii) Fuel Cell

18. The resistance of 0.5 M CH3COOH solution is 100 ohm. The cell constant is 0.035

cm1.

19. Calculate molar conductivity of solution.

20. Chromium metal can be plated out from acidic solution containing CrO3 according

to following reaction-

21. Calculate the mass of chromium that will be plated out by 12000 C of charge.

22. (i) Why is the salt bridge used in electrochemical cell?

(ii) Name an electrode which is used as a reference electrode? Give its diagram and

working.

(iii) How does electrochemical series help in the following:

(a) Comparing the relative oxidizing or reducing properties of elements.

(b) Predicting the reactivity of a metal with acid.

23. Calculate the equivalent conductivity of 1 m H3PO4 solution whose conducting is 25

x 152 Scm-1.

24. Calculate the resistance of 0.01N solution of an electrolyte whose equivalent

conductivity is 328 ohm-1 cm2equiv-1. (The cell constant of the cell is 0.88 cm-1)

25. A solution containing 2 g of anhydrous BaCl2 in 400cm3 of water has a conductivity

of 0.0058 S cm-1. Calculate the molar & equivalent conductivity of this solution.

26. A 0.05 M KOH solution offered a resistance of 31.6 ohm in a conductivity cell. If the

cell constant of cell is 0.367 cm-1. Calculate the molar conductance.

27. The value of Molar conductance at infinite dilution forHCl, NaCl& CH3COONa are

426.1,126.5 & 91.0 S cm2 mol-1respectively. Calculate the molar conductivity of

acetic acid at infinite dilution



1,3,5,7,9,11,13,15,17,19,21,23,25,27,29


28. Why does the conductivity of an electrolyte decreases with dilution whereas molar

conductivity increases?

29. The conductivity of BaSO4 was found to be 3.6 x 10-6 S cm-1 and that of water is

1.25 x 10-6 S cm-1. The for Ba2+ and SO42- ions are 110 & 136.6 S cm2 mol-

1 respectively. Calculate the solubility of BaSO4 in gram per litre. (Atomic mass of

Ba=137, S=32,O=16).

30. Write the half cell reaction and net cell reaction for the following electrodes

(i) Ni/Ni2+ || Ag+/Ag (ii) Cr/Cr3+ || Pb2+/Pb

31. Find emf of H2O2 fuel cell from the following data

32. Find the emf of following cell

12131 ARUN BAGHEL PRESENCE OF INSECTISIDES AND PESTICIDES IN FRUITS.


END OF CHEMISTY HOME-WORK

SUBJECT: - HINDI

1 | 2 ' 250 |

250 |

3 | 4 03 | 5 |

SUBJECT: - BIOLOGY

Note: Explain the following questions in details and draw diagram/ flowchart where ever necessary.

Q.1 Honeybees produce their young ones only by sexual reproduction. Draw diagram of

Honeybees reproductive life cycle.

Q.2 With a neat labelled diagram describe the parts of a typical angiosperm ovule.

Q.3 With a neat labelled diagram explain the 7-celed, 8- Nucleate nature of the female

gametophyte. Explain various steps followed during gametophyte formation.

Q.4 What is meant by emasculation? When and why does a plant breeder eploy this technique?

Q.5 Identy each part in flowering plant and write weather it is diplois (2n) or Haploid (n)?

(i) Ovary (ii) Anther (iii) Egg (iv) Pollen (v) Male gamete (vi) Zygote

Q.6 Starting with the zygote draw the diagrams of the different stage of embryo development in

a dicot plant.

Q.7 Draw a labble diagram of male and female reproductive system.

Q.8 Explain harmone regulations of oogenesis and spermatogenesis (flow chart).


Q.9 Draw labelled diagram of Human sperm. Write short notes also.

Q.10 In our society the women are often blammed for giving birth to daughters. Can you expalin

why it is not correct?

Q.11 Meiotic division during oogenesis is diferent from that in spermatogenesis. Explain

diagrametically.

Q.12 What are the suggested reasons for population explosion?

Q.13 Removal of gonads cannot be considered as a contraceptive option. Why?

Q.14 Amniocentesis for sex determination is banned in our country. Is this technique very much

hadarzous to society? Comment.

Q.15 Suggest some methods to assists infertile couples to have children. (Explain each method)

Q.16 What are the measures one has to take to prevent contracting STDs?

Q.17 Stict condition/steps are to be followed in medical termination of pregnancy (MTPs)

procedure. Mention two reasons.

Computer Science

NOTE - Prepare a 50 page copy for summer assignment.

1. Write any fifteen C++ programs using following:-

i. For Loop ii. While Loop iii. Do While Loop iv Conversion of IF statement into switch statement v. Conversion of Switch statement into if statement vi. Function vii. Structure viii Union ix Class & Object x Call By Value xi Call by Reference xii. Nested For Loop xiii Nested While Loop xiv Nested Do while Loop xv Array.


2. Write two portions of Solved Board Exams question paper including unit iii -

Database, iv - Boolean Algebra & v - Networking

3. Write question answer of any one Class XI Solved question paper.

4. Write any ten SQL statement with syntax.

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