KENDRIYA VIDYALAYA BAILEY ROAD SECOND SHIFT HOLIDAY HOMEWORK CLASS: XII SUB: HINDI

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1 KENDRIYA VIDYALAYA BAILEY ROAD HOLIDAY HOME WORK CLASS: XII SUB: ENGLISH Q.1. Write a letter to the Editor. Q.2. Write a complaint. Q.3. Write a Job application. Q.4. Write a comprehension. Q.5. Write a passage. Q.6. Write a notice. Q.7. Write an advertisement. Q.8. Write a poster. Q.9. Write a report. Q.10. Write an article. Q.11. Book review of 12 Chapters of The Invisible Man. KENDRIYA VIDYALAYA BAILEY ROAD HOLIDAY HOMEWORK CLASS: XII SUB: HINDI ग र ष मkवक श ग ह -क र य आर ह भ ग २ Xk [kam १ भक त न २ ब ज र दशयन i [kam 1. आत म-पररचर 2. प ग प रक प स क वव न भ ग -२

2 1 ड र र क पन न इन सभ प ठ क प रश न त तर ल ख a एव इसक अत ररत ५-५ घ त तर र प रश न त तर ल ख a 1 व र करण पत र - खन vki fdlh i;zvd LFky ij Hkze.k ds fy, x, fdurq ogkw dh vlopnrk ns[kdj f[kuu gq,a bl ij vius fopkj O;Dr djrs gq, mdr LFky ds i;zvu vf/kdkjh dks,d i= fyf[k, vksj lq/kkj dk vuqjks/k dhft,a तनब ध - खन ( ककन ह,d ) 1. प र क त क आपद एWa 2. बद र ग - बद म न र ए ३ iqlrdks a dk egroa फ चर खन १ स वच छ अलभर न २ म हग ई KENDRIYA VIDYALAYA BAILEY ROAD HOLIDAY HOME WORK CLASS: XII SUB: MATHEMATICS Q.1. Do five years AISSCE questions from the chapter taught. Q.2. Do all the examples given in NCERT book of class XII from the chapters taught KENDRIYA VIDYALAYA BAILEY ROAD HOLIDAY HOME WORK CLASS: XII SUB: PHYSICS Q1. Two point charges q 1 and q 2 are placed close to each other. What is the nature of the force between them when: (i) q 1q 2 < 0 and (ii) q 1q 2 >0? 1 Q2. Name the quantity with unit J/C. Is it a scalar or vector quantity? 1 Q3. An electric dipole of dipole moment 2x10-6 C m is enclosed by a closed surface. What is the flux passing out of the surface? 1 Q4. What is the angle between the directions of electric field at any (i) axial point and (ii) equatorial point due to an electric dipole? 1

3 Q5. Two point charges placed at a distance r in air exert a force F on each other. At what distance will these charges experience the same force F in a medium of dielectric constant K? 1 Q6. Consider a dipole of length 2a. What is the magnitude and direction of electric field at the mid point of the length of the dipole 2 Q7. Two charges +10µC and -20µC are placed 15 cm apart. At what point on the line joining the two charges is the electric potential zero? 2 Q8. The following data was obtained for the dependence of the magnitude of electric field, with distance, from a reference point O, within the charge distribution in the shaded region. 2 (i) (ii) Identify the charge distribution and justify your answer. If the potential due to this charge distribution has a value V at the point A, what is its value at the point B and C. Q9. Derive expression for electric field at a point on the equatorial line of dipole. 3 Q10. Using Gauss Theorem, show mathematically that for a point outside a shell, the field due to a uniformly charged thin shell is the same as if the entire charge of the shell is concentrated at the centre. Why do you expect electric field inside the shell to be zero according to this theorem? 3 Q11. An electric dipole of dipole moment p is placed in a uniform electric field. Write the expression for the torque 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. 3 Q12. Derive expression for energy stored in parallel plate capacitor. Net capacitance of three identical capacitors in series is 1µF. What will be their net capacitance if connected in parallel? Find the ratio of energy stored in the two configurations if they are both connected to the same source. 5 AISSCE QUETIONS 1. A 10 V battery of negligible internal resistance is connected across a 200 V battery and a resistance of 38 Ω. Find the value of the current in circuit.

4 E A: I = r R = 5A The plot of the variation of potential difference across a combination of three identical cells in series, versus current is as shown below. What is the emf of each cell? A: Let E be emf of each cell and r be the total internal resistance of circuit. The equation of terminal potential difference V 3 E Ir (1) At V = 6V, I = 0. Therefore from eq (1), 6 3E 0 E 2V 3. When electrons drift in a metal from lower to higher potential, does it mean that all the free electrons of the metal are moving in the same direction? A: No. 4. A steady current flows in a metallic conductor of non-uniform cross-section. Which of these quantities is constant along the conductor: Current, current density, drift speed, electric field? A: Current is constant along a conductor. 5. Two wires of equal length, one of copper and the other of manganin have the same resistance. Which wire is thicker? l M AM A: R since RC RM and lc lm but M C 1 AM AC A A The manganin wire is thicker. 6. A resistance R is connected across a cell of emf e and internal resistance r. A potentiometer now measures the potential difference between the terminals of the cell as V. Write the expression for r in terms of E, V and R. E V A: r = R V 7. Two conducting wires X and Y of same diameter but different materials are joined in series across a battery. If the number density of electrons in X is twice that in Y, find the ratio of drift velocity of electrons in the two wires. A: In series current is same I X = I Y. For same diameter, cross-sectional area is same. C C

5 n eav x x n eav y y v v x y n n y x A conductor of length L is connected to a dc source of emf V. If this conductor is replaced by another conductor of same material and same area of cross-section but of length 3L, how will the drift velocity change? ev 1 A: v d ml L When the length is made 3L, the drift velocity becomes one third. 9. A wire of resistance 8 R is bent in the form of a circle. What is the effective resistance between the ends of a diameter AB? A: Two parts each of resistance 4R are connected in parallel; so effective resistance across ends of diameter AB is 2R 10. State Kirchhoff s rules. A: Kirchhoff s Rules: (i) The algebraic sum of currents meeting at any junction is zero, i.e. I = 0 (ii) The algebraic sum of potential differences across circuit elements of a closed circuit is zero,i.e., V = Write any two factors on which internal resistance of a cell depends. A: The internal resistance of a cell depends on (i) distance (l) between electrodes. (ii) area (A) of immersed part of electrode, and (iii) nature and concentration of electrolyte. 12. The following graph shows the variation of terminal potential difference V, across a combination of three cells in series to a resistor, versus the current, I. (i) Calculate the emf of each cell. circuit be maximum? (ii) For what current I will the power dissipation of the A: (i) Let E be emf of each cell and r be the total internal resistance of circuit. The equation of terminal potential difference V 3 E Ir (1) At V = 6V, I = 0. Therefore from eq (1), 6 3E 0 E 2V

6 (ii) At V = 0V, I = 2A. Therefore from eq (1), 0 6 2r r 3 (iii) For maximum power dissipation, external resistance (R) = Internal resistance (r) Current, I = 3E r R 6 = 1A A conductor of length l is connected to a dc source of potential V. If the length of the conductor is doubled by gradually stretching it, keeping V constant, how will (i) drift speed of electrons and (ii) resistance of the conductor be affected? Justify your answer. ev 1 A: (i) v d ml L Thus, the length is doubled, the drift velocity becomes half. (ii) l R A When the length of the conductor is doubled, the area of cross section becomes half. New resistance ' 2l l R 4 4R A A 2 Thus, the length is doubled, resistance becomes four times. 14. Two students X and Y perform an experiment on potentiometer separately using the circuit given. Keeping other parameters unchanged, how will the position of the null point be affected it (i) X increases the value of resistance R in the set-up by keeping the key K 1 closed and the key K 2 open? (ii) Y decreases the value of resistance S in the set-up, while the key K 2 remain open and the key K 1 closed? Justify. A: (i) By increasing resistance R the current through AB decreases, so potential gradient decreases. Hence a greater length of wire would be needed for balancing the same potential difference. So the null point would shift towards B. (ii) By decreasing resistance S, the current through AB remains the same, potential gradient does not change. As K 2 is open so there is no effect of S on null point. 15. Plot a graph showing temperature dependence of resistivity for a typical semiconductor. How is this behaviour explained?

7 A: Variation of resistivity with temperature is shown below: Explanation: In semiconductor the number density of free electrons (n) increases with increase in temperature (T) and consequently the relaxation period decreases. But the effect of increase in n has higher impact than decrease of ρ. So, resistivity decreases with increase in temperature. 16. (a) You are required to select a carbon resistor of resistance 47 k Ω ± 10% from a large collection. What should be the sequence of colour bands used to code it? (b) Write the characteristics of manganin which make it suitable for making standard resistance. A: (a) Sequence of colour should be: Yellow, Violet, Orange and Silver (b) (i) Very low temperature coefficient of resistance. (ii) High resistivity 17. In the given circuit, assuming point A to be at zero potential, use Kirchhoff s rules to determine the potential at point B. A: By KCL, current in DC branch I = 3-1 = 2A Applying KVL along path ACDB, VA VB VB VA V 18. Define drift velocity. Write its relationship with relaxation time in terms of the electric field E applied to a conductor. A potential difference V is applied to a conductor of length L. How is the drift velocity affected when V is doubled and L is halved? A: Drift velocity is defined as the average velocity with which the free electrons get drifted towards the positive end of the conductor under the influence of an external electric field applied. It is given by v d ev ml When V is doubled and L is halved, the drift velocity becomes 4 times. 19. Define ionic mobility. Write its relationship with relaxation time. How does one understand the temperature dependence of resistivity of a semiconductor? A: Mobility of an ion is defined as the drift velocity per unit electric field.

8 μ = E v d = m e τ. Its unit is m 2 /Vs. When temperature increases, covalent bonds of neighbouring atoms break and charge carriers become free, so resistivity of semi-conductor decreases with rise of temperature. 20. State the principle of working of a potentiometer. Define potential gradient and write its S.I. unit. A: Principle of potentiometer - When a constant current flows through a wire of uniform crosssectional area, the potential drop across any portion of the wire is directly proportional to the length of that portion. The fall of potential per unit length along potentiometer wire is called the potential gradient. The S.I. unit of potential gradient is volt/metre. 21. State the principle on which the working of a meter bridge is based. Under what condition is the error in determining the unknown resistance minimized? A: the working of a meter bridge is based on the principle of Wheatstone s bridge. To minimize the error in determining the unknown resistance, the position of balanced point should be in the middle of meter-bridge wire. 22. Calculate the current drawn from the battery in the given network. A: The equivalent circuit is shown in fig. The five resistors form a balanced Wheatstone s bridge. Since So, R 2 is ineffective. The effective resistance of R 1 and R 5 in series, R = R 1 + R 5 = = 3 Ω The effective resistance of R 4 and R 3 in series is R = R 4 + R 3 = = 6 Ω R1 R 5 R R 4 3 R and R are in parallel. Therefore the Equivalent resistance of network between A and B, R AB ' '' R R 2 ' '' R R

9 Current drawn from battery, I R E '' AB 4 2A A wire of 15 Ω resistance is gradually stretched to double its original length. It is then cut into two equal parts. These parts are then connected in parallel across a 3 volt battery. Find the current drawn from the battery. A: When the length of the wire is doubled, the area of cross section becomes half. New resistance ' 2l l R 4 4R 60 A A 2 Resistance of each half part is 30Ω. When both parts are connected in parallel, Equivalent resistance = Current drawn from battery, I V R eq 3 0.2A Use Kirchhoff s rules to show that no current flows in the given circuit. A: Applying KVL in loop bcda, 2 Ir Ir 2 0 I 0A 2 1 KENDRIYA VIDYALAYA BAILEY ROAD HOLIDAY HOME WORK CLASS: XII SUB: CHEMISTRY 1. How does a glass pane fixed to window give the evidence of fluidity in glass? 2. Draw diagrams to show differences in crystal structures of diamond and graphite. 3. Draw different kinds of unit cells. 4. Atoms of element B form hcp lattice and those of the element A occupy 2/3 of tetrahedral voids. What is the formula of the compound formed by the elements A and B? 5. X-ray diffraction studies show that copper crystallises in a fcc unit cell with cell edge of x 10 8 cm. In a separate experiment, copper is determined to have a density of 8.92 g/cm 3. Calculate the atomic mass of copper. 6. Match the items of column A with that of column B Column A Column B (a) Stoichiometric defect (i) decrease in density (b) Vacancy defect (ii) NaCl (c) Interstitial defect (iii) AgCl (d) Frenkel defect (iv) intrinsic defect (e) Schottky defect (v) increase in density

10 7. Name an oxide that is like copper in its conductivity and appearance. 8. Explain how vacancies are introduced in an ionic solid when a cation of higher valence is added as an impurity in it. 9. Calculate (a) molality (b) molarity and (c) mole fraction of KI if the density of 20% (mass/mass) aqueous KI is g ml Explain Raoult s law for a solution of volatile liquids. 11. What type of deviation from Raoult s law is shown by a mixture of chloroform and acetone? Why? 12. Determine the osmotic pressure of a solution prepared by dissolving 25 mg of K 2SO 4 in 2 L of water at 25 0 C, assuming that it is completely dissociated. 13. Benzene and toluene form ideal solution over the entire range of composition. The vapour pressure of pure benzene and naphthalene at 300 K are mm Hg and mm Hg respectively. Calculate the mole fraction of benzene in vapour phase if 80 g of benzene is mixed with 100 g of naphthalene. 14. Q. 3.5 of page 91 (Exercise of Electrochemistry) of NCERT book. 15. What happens when an external opposite potential is applied in the galvanic cell and increased slowly? KENDRIYA VIDYALAYA BAILEY ROAD HOLIDAY HOMEWORK CLASS: XII SUB: BIOLOGY Q.1. Do five years AISSCE questions for the Chapters- III Human Reproduction. IV Reproductive Health. V Principles of Inheritance. Q.2. Write & Learn NCERT questions of UNIT I and Chapter V. Q.3. Prepare comparative chart between the followingi. Micro Sporogenim and Megarporogenim ii. Sperm atogenim and Oogenim iii. Development of dicot embryo and human embryo development.

11 KENDRIYA VIDYALAYA BAILEY ROAD CLASS: XII HOLIDAY HOMEWORK SUB: COMPUTER SCIENCE Ques 1. Differentiate between post and pre increment operator. Also give a suitable C++ code to illustrate both. Ques 2. Differentiate between actual and formal parameter. Also give a suitable C++ code to illustrate both. Ques 3. Differentiate between local variable and global variable. Also give a suitable C++ code to illustrate both. Ques 4. Differentiate between type casting and automatic type conversion. Also give a suitable C++ code to illustrate both. Ques 5. Differentiate between call by value and call by reference. Also give a suitable C++ code to illustrate both. Ques 6. Differentiate between run time error and syntax error. Also give a suitable C++ code to illustrate both. Ques 7. Differentiate between class and structure. Also give a suitable C++ code to illustrate both. Ques 8. Differentiate between #define and const. Also give a suitable C++ code to illustrate both. Ques 9. Differentiate between logical error and syntax error. Also give a suitable C++ code to illustrate both. Ques 10. What is the purpose of using a typedef command in C++? Explain with suitable example. Ques 11. What is Object oriented programming? How it is different from Procedural Programming? Ques 12. What do you understand by Data Encapsulation and Data Hiding? Also give a suitable C++ code to illustrate both. Ques 13. What do you understand by Polymorphism? Explain with suitable example. Ques 14.

12 Ques 15. Ques 16 Ques 17

13 Ques 18 Ques 19. What do you mean by Function Overloading? Explain it with suitable C++ code. Ques 20