ह न द MATHS. 1. Maths class xii sample paper I 2. Maths class xii sample paper II 3. Maths class xii sample paper III CHEMISTRY

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1 CLASS XIIB ENGLISH 1. You are Jeet/Jyothi, Head Boy/Girl of KV IMA Premnagar, Dehradun. Write a notice for your school informing about Grandparents Day to be held in your school and ask the student to actively participate in it.give necessary details. 2. You are the secretary of your Vidyalaya s newly formed Nature Club write a notice in not more than for your Vidyalaya, inviting the students of classes IX to XII to join the Nature Club to beautify the school. You are Surya/Sakshi Pradhan of KV IMA Premnagar, Dehradun. 3. Principal, Kendriya Vidyalaya, Ind. Milit. Acad., Dehradun Cantt requires a receptionist for her school. Prepare a suitable advertisement in not more than 50 words to be published in the classified columns of Doon Classifieds giving all necessary details of eligibility criteria and work experience needed in the candidate. 4. You are Jitendra/Priyanka of M-15/3, MT Colony, Ind. Milit. Acad., Dehradun Cantt You want to sell your motor bike. Draft a suitable advertisement in not more than 50 words to be published in the classified columns of Doon Classifieds giving all necessary details. 5. International Tobacco Control Programme is an organisation that is working worldwide to spread awareness about the hazards of tobacco use. Design/Prepare an attractive poster for the organisation in not more than 50 words mentioning the harmful effect of smoking and tobacco consumption in other forms. 6. Design a poster in not more than 50 words covering on the importance of healthy and nutritious food in our life. Invent all necessary details viz: a catchy slogan, tips to remember, a picture and issuing authority etc. 7. As the resident of Barrack No.-37/7, Special Wing, Premnagar, Dehradun , write a letter to the editor of a local daily regarding the long power cuts that your colony has to face every day and the resultant problems being faced by the residents, in not more than 150 words. 8. Your are Arifa/Imran, Principal Sahara Global School, NH-37, Manesar (HR) Use the clues given below to write a letter of inquiry to the Chairman, Delhi Transport Corporation asking for details regarding availability of buses for school transport. You can use the following clues to write the letter in not more than 150 words. Number of buses. Capacity. Flexible timings. Charges for the whole month. Security. 9. Teenagers today are getting hope on the latest gadgets like mobiles, Ipods, Computers. Write an article on The Advantages of Technology V/S Its Adverse Effects you are Soumya/Saurabh Taneja. Write the article in not more than 150 words 10. You are Manju/ Manjeet. You are much concerned about the rise in the incident of road rage in the state capital. Write an article in not more than 150 words on Road Rage: A Deadly Threat 11. Attempt the character sketch of 1. Griffin: The Invisible Man, 2. Mrs. Hall: The Inn Keeper, 3. Mr. Marvel: A Local Tramp, 4. Dr. Kamp, in not more than 120 words. 12. Attempt the note making of the episodes of The Burglary at Vicarage and The Jolly Cricketer Bar in a format you consider suitable. Use abbreviations wherever necessary. Attempt the summaries of both the episodes in not more than 80 words each.

2 CHEMISTRY MATHS Solve the Questions of the topics from Chapter 1 to Chapter 7 in separate Note Book from the following Three Sample Papers already given to the students: 1. Maths class xii sample paper I 2. Maths class xii sample paper II 3. Maths class xii sample paper III ह न द 1 गत वर ष क ब डष क प रश न पत र ल कर (प रश न पत र ह पक ए ) 2 ड यर क पन न स प ठ पढ़ और प रश न त तर कर 3 क व य लय स ईट क नवक स म भ ग स एक स न दर तथ प र रण द य कहवत क यन कर उसक प रहतहलहप ल और ह पक ए तथ उस क ठस थ कर कक ष म स न ए 4. छ त र ए प त र क ड यर स प र ररत कर ल ख हलख और छपन क हलए द छ त र भ सम ज म ककय ज र ऐस प रय स पर अपन हव र रख स थ य भ बत ए कक और क य प रय स ककय ज सकत?

3 PHYSICS Electric Force and Field: 1. Draw a plot showing the variation of i. Electric field and ii. Electric potential with distance r due to a point charge Q. 2. Plot a graph showing the variation of Coulomb s force F versus 1/r2, where r is the distance between the two charges of each pair of charges: (1µC, 2µC) and (1µC, -3µC). Interpret the graphs obtained. 3. Deduce the expression for the electric field E due to a system of two charges q1 and q2 with position vectors 1 r and 2 r at a point at r with respect to common origin. Gauss Law: 4. Draw the shapes of suitable Gaussian surfaces, while applying Gauss law to calculate the electric field due toi. A uniformly charged long straight wire. ii. A uniformly charged infinite plane sheet. 5. Define electric flux. Write its SI unit. A spherical rubber balloon carries a charge q 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 of the balloon change? Give reason. Electric potential: 6. Draw an equipotential surface for a system of two similar and opposite charges. 7. Two charged conducting spheres of radii r1 and r2 connected to each other by a wire. Find the ratio of the electric fields at the surfaces of the two spheres. 8. Define the dipole moment of an electric dipole. How does the electric potential of an electric dipole vary on the dipole axis as a function of distance r of the point from the midpoint of the dipole at large distances? (AI 2008C) Potential Energy and Work done: 9. A fully charged capacitor is disconnected from the battery and the plates are pulled apart. What will happen to the potential energy of the capacitor? If there is any increase in energy, explain the source of additional energy. Electric capacitance: 10.What is the function of a dielectric slab in an electric capacitor? 11.Define the dielectric constant of a medium. Briefly explain why the capacitance of a parallel plate capacitor increases on inserting a dielectric slab in between the plates?

4 CONCEPTUAL QUESTIONS: 12.The emf of a cell is greater than its terminal voltage. Give reason. 13.Two wires of equal length, one of copper and the other of manganin have the same resistance. Which wire is thicker? 14.In an experiment on Meter Bridge, the balancing length AC is X. What would be its value, when the radius of the meter bridge wire is doubled? Justify your answer. Current and Drift Velocity: 15.Show on a graph, the variation of resistivity of a typical semiconductor with temperature. 16.A conductor of length l is connected to a potential difference V. of the length of the conductor is tripled, by gradually stretching it, keeping V constant, how willa. Drift speed of the electrons will change? b. Resistance of the conductor will be affected? 17.Derive an expression for drift velocity of electrons in terms of relaxation time of electrons. 18.Derive an expression for the resistivity of a good conductor, in terms of relaxation time of electrons. 19.Derive an expression for the current density of a conductor in terms of drift velocity of electrons. 20.Write the mathematical relation for the resistivity of a material in terms of relaxation time, number density, mass and charge on the charge carriers in it. Explain using the relation, why the resistivity of a material increases and that of a semiconductor decreases with rise in temperature. Resistance and Ohm s law: 21.The three coloured bands on a carbon resistor are red, green and yellow respectively. Write the value of the resistance. 22.Write an expression for the resistivity of a conductor showing its variation over a limited range of temperature. Emf and Internal Resistance: 23.The emf of a cell is always greater than the terminal voltage. Why? Give reason. 24.A resistance R is connected across a cell of emf E and internal resistance r. Now a potentiometer measures the potential difference between the terminals of the cells as V. Write the expression for r in terms of E, V and R. and internal resistance r is connected across a variable resistor R. plot a

5 25.A cell of emf graph showing the variation of terminal voltage V with R. 26.Plot a graph showing the variation of terminal potential difference V across a cell of emf and internal resistance r with current drawn from it. Using the graph show how emf of the cell can be determined? Combination of cells: 27.Two identical cells each of emf E, having negligible internal resistance are connected in parallel with each other across an external resistance R. what is the current through this resistance? Ans: E/R and internal resistance 2r and r are connected in parallel. Obtain and 28.Two cells of emf 2 the expressions for equivalent emf and internal resistance., internal resistance r are connected in series 29.A number of identical cells n, each of emf o using a resistor. are charged by a battery of emf a. Draw the circuit arrangement. b. Deduce the expressions for i. The charging current and ii. The potential difference across the combination of the cells. Meter Bridge: 30. In the meter bridge experiment, balance point was observed at J with AJ=l. a. The values of R and X were doubled and then interchanged. What would be the new position of balance point? b. If the galvanometer and battery are interchanged at the balance position, how will the balance point get affected? 31. Obtain the balance condition for Wheatstone bridge using Kirchhoff s laws. Potentiometer:

6 32. The variation of potential difference with length in case of two potentiometers A and B is shown in the figure. Which of these two will you prefer for comparing the emfs of two primary cells? 33. A series and parallel combination of two resistors is connected, one by one, across a cell. In which case will the terminal voltage, across the cell, have a higher value? 34. For the potentiometer circuit shown in the figure, X and Y represent two terminals of a cell of unknown emf. A student observed that when the jockey is moved from the end A to the end B of the potentiometer wire, the deflection in the galvanometer remains in the same direction. What may be the two possible faults in the circuit that may result in this observation? If the galvanometer deflection at the end B is (a) more, (b) less, than at the end A, which of the two faults, listed above, would be there in the circuit? Give reason in support of your answer in each case. 35. A wire of resistance R is stretched to double its length. What will be its resistance and resistivity? 36. Compare the resistance of two wires of same material. Their lengths are in the ratio 2:3 and their diameters are in the ratio 1:2. Ans:R1: R2=8:3 37. With two resistances R1 and R2 in the two gaps of a meter bridge, the null point is obtained at 1/3m from the zero end. When a resistance of 6 is

7 connected in series to the smaller of the resistances, the null point is shifted to 2/3 m form the same end. Calculate R1 and R2. Ans: R1=2 and R2=4 38. What s the effective resistance of the following circuits? Ans: R, R/2, AB is a potentiometer wire. If the value of resistance R in the driving circuit is increased, in which direction will the balance point J shift? 40. An electron of hydrogen atom is revolving around the nucleus in the circular orbit of radius with velocity. What is the equivalent current in the atom? Ans 2224hme 22eh 534meh 41. A hollow cylinder of length l and radius a and b is filled with a material of resistivity and is connected to a battery of emf through an ammeter, as shown in the figure. Find the current through the ammeter. 42. Why potentiometer is preferred over voltmeter for measuring emf? 43. Manganin is used for standard resistors. Why? 44. A conductor of length l is connected to a DC source of potential V. if the length of the conductor is tripled by stretching it. Keeping V constant, explain how do the following factors vary in the conductor: a. Drift speed of the electrons b. Resistance and resistivity. 45. A current is passed through a cylindrical conductor of gradually decreasing radius. At which point the drift speed of the electrons will be higher? 46. Two wires of same dimension but resistivity 1 and 2 are connected in series and than in parallel. Find out the equivalent resistivity for each case. 47. Current is allowed to flow through a metallic wire at a constant potential difference. When the wire becomes hot, cold water is poured on half portion of it. By doing so, the other portion becomes hotter. Explain.

8 48. A battery is first connected across a resistor R1 and then to R2. Find the value of internal resistance r of the battery for which the heat released in external circuit be same in both the cases. Ans: 12RR 49. A cell supplies current i1 through a coil of resistance R1 and a current i2 through another coil of resistance R2. What is the emf and internal resistance of the cell? 50. Two cells each of equal emf but of internal resistance r1 and r2 are connected in series through an external resistance R. Find the value of R in terms of r1 and r2 for which first cell will have zero potential difference across it. BIOLOGY