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SAMPLE QUESTION PAPER - 2009 PHYSICS - XII Time: 3hrs. Max. Marks.: 70 General Instructions : 1. All questions are compulsory. 2. There are 30 questions in total.Questions 1 to 8 carry one mark each, questions 9 to 18 carry two marks each, questions 19 to 27 carry three marks each and questions 28 to 30 carry five marks each. 3. There is no overall choice. However, an internal choice has been provided in all three questions of five marks each. You have to attempt only one of the given choices in such questions. 4. Use of calculators is not permitted. 5. You may use the following physical constants wherever necessarry. c=3 108 ms-1, h=6.6 10-34 Js, e= 1.6 10-19 c, m A-1, Boltzmann's constant k=1.38 10-23 J K-1, Avogadro's number NA = 6.023 1023 mol-1, mass of neutron mn = 1.6 10-27 kg. 1. Two identical charged particles moving with same speed enter a region of uniform magnetic field. If one of these enters normal to the field direction and the other enters along a direction at 30 0 with the field, what would be the ratio of their angular frequencies? 1 2. Two identical charged particles moving with same speed enter a region of uniform megnetic field. If one of these enters normal to the field direction and the other enters along a direction at 30o with the field, what would be the ratio of their angular frequencies? 1 3. How is a sample of an n-type semiconductor electrically netural though it has an excess of negative charge carriers? 1 4. The power factor of an circuit is 0.5. What will be the phase difference between voltage and the current?1 5. A partially plane polarised beam of light is passed through a polaroid. Show graphically the variation of the transmitted light intensity with angle of rotation of the polaroid. 1 6. Calculate the ratio of energies of photons produced due to transition of electron of hydrogen atom from its, i) Second permitted energy level to the first level, (ii) highest permitted energy level to the second permitted level. 1 7. Explain how is solar cell different from photodiode. 1 8. What will be the values of inputs A and B for the Boolean expression ( A + B ) (A , B ) = 1 1 9. Keeping the voltage of the charging source constant, what would be the percentage change in the energy stored in a parallel plate capacitor if the separation between its plates were to be decreased by 10%? 2 10. Draw a circuit diagram of a meter bridge to determine the resistance of a wire. Give the formula used. 2
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