CBSE Physics Model Question Paper- II
1. Why two similar charges repel each other?
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2. What is the principle of potentiometer?
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3. What is the name given to A. B + A. B gate?
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4. A wire of resistivity p is stretched so that its length becomes double and area half the original. How will the resitivity be affected?
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5. A lens is taken and a small piece of it is removed from the centre as shown in fig¬ure (b). How the focal length of the lens is going to be effected in comparison with original lens A?
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6. Define resolving power of an instrument.
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7. Define magnitude of a star.
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8. Is dry cell really dry from inside? Explain in one, two lines.
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9. What is electromagnetic damping? Where is it used?
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10. If critical angle for a pair of medium is 30°, what is the angle of polarisation for the pair?
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11. Distance of Venus is 0. 7 A.U. Find the orbital period of Venus in terms of earth days.
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12. 1 atomic mass unit of substance is completely destroyed in a nuclear reaction, what is the energy produced in MeV?
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13. Frequency of incident radiations on a metal surface is tripled, how will K.E. of ejected electrons be effected?
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14. A 44 ohm resistor is used on 220 V supply for 2 hours. What are the expenses if 1 B.O.T. costs Rs.2-50?
15. A horizontal overhead power line carries a current of 5 A in west to east direction. What is the magnitude and direction of magnetic field due to current 2 - 5 m below the line ?
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16. What is the difference between resistance, reactance and impedance ? Who arc they connected?
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17. What is an optical fibre? Give one of its important applications.
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18. What is depletion layer? Draw these in case of forward and reverse biasing P-N junction diode.
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19. Find the minimum number of cells required to produce an electric current of 1 .5 A through a resistor of 30 ohm, given that the emfs of each cell is 1.5 V and internal resistance of each cell is 1 Ω.
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20. What are the laws of photoelectric emission? Explain these with the help of Einstein’s equation.
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21. Distinguish between conductors, semiconductors and insulators on the basis of their energy bonds.
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22. What are the laws of radioactive disintegration? Deduce the value of the number of atoms left after some time.
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23. Find the magnitude and direction of the force between two parallel conducting wires carrying current and hence define an ampere.
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24. What is solar constant? How does it help us to know the temperature of the sun?
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25. What is neutral temperature and temperature of inversion and thermoelectric power? What is thermoelectric power at neutral temperature?
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26. What is constringence? How is it related to refracting indices for different colours?
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27. Two small spheres each of mass 0. 09 kg hang by equal silk threads attached to the same point. The spheres are charged and made to touch each other. They come to rest with their centres 0.02 m apart and 0.20 m vertically below the point of support. Find the charge on each sphere
if g = 9-8 ms-2.
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28. What is Huygen principle? How SnelFs law can be deduced using this principle?
Twelve wires each of resistance 4 Ω are. Joined to form a skelton cube. Determine the resistance across any of the wire forming the cube.
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29. Describe principle, construction and working of a D.C. generator. How can smooth output be got from it?
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30. Deduce lens formula for convex len. Give sign conventions and assumptions followed.
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