CBSE Physics Sample Question Paper : Set-7
Q. 1. State two factors on which the sensitivity of a moving coil galvanometer depends.
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Q. 2. What is the physical quantity measured by kilogram metre per cubic second per ampere?
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Q.3. A glass rod whenrubbed with silk acquires a charge + 1.6 X 10-12 C. What is the charge on the silk?
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Q.4. The wavelength of an electro magnetic wave is 10 mm, to what part of the spectrum it belongs?
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Q. 5. In an a.c. circuit why there is no power consumption in an inductor?
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Q. 6. Name a device for producing polarised light
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Q. 7. A conducting loop of radius r carries a constant current i and is placed in a uniform magnetic Held B such that B is perpendicular to the loop. What is the magnetic force acting on the loop?
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Q. 8. Give the main reason for the necessity of ozone layer for the survival of life on the earth.
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Q. 9. How can paramagnetic and diamagnetic material rods be distinguished in a magnetic field?
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Q. 10. Give any two differences between Asteroids and Meteoroids.
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Q. 11. What percentage of a given mass of a radioactive substance will be left undecayed after five half-life periods?
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Q. 12. The work function of aluminium is 4.2 eV. If two photons each of energy 2.3 eV strike together a surface electron of aluminium, what is the energy of the photons emitted?
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Q. 13. Show graphically the variation of charge q with time t, when a condenser is charged. Write the equation for the graph.
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Q. 14. An electron is projected with a velocity of 105 ms-1 at right angles to a magnetic field of 0.19G. Calculate the radius of circle described
by electron. (Given e 1.6 x 10 -19 Coulomb, m = 9.1 x 10-31 kg).
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Q. 15. A concave spherical mirror of focal length 30 cm is to be used to form a real image thrice the size of the object. What object distance should be used?
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Q. 16. The mass of a proton is much larger than the electron. An electron and proton of equal kinetic energies, enter perpendicularly a uniform electric field. Which of the paths is more curved?
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Q. 17. Why do we use short waves for long distance radio broadcast?
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Q. 18. Two wires of the same material having lengths in the ratio of 1: 2 and diameteres in the ratio 2: 3 are connected in series with an accumulator. Compute the ratio of the p.d. across the two wires.
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Q. 19. If different isotopes of the same element have the same chemical behaviour how can they be separated?
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Q. 20. What is an electromagnet? Give two uses of an electromagnet.
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Q. 21. What is half-life? A radioactive sample has 8.0 x 10-18 active nuclei when we start counting time. How many of these nuclei will still be in the same state after two half-lives?
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Q. 22. Deduce the expression for fringe width in Young’s double slit experiment.
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Q. 23. An electron is projected towards the positive plate of a parallel plate capacitor charged to a potential difference V. A magnetic field B also exists between the plates. What must be the minimum separation d between the plates so that the electron does not fail to strike the positive plate?
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Q. 24. In a magnet, neutral points are found along the axis of the magnet In what direction the magnet is placed? Write the expression connecting magnetic moment m of the magnet and the earth’s horizontal component.
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Q. 25. Sun’s angular diameter is about 0.5°. Its distance from earth is about 1.5 x 108 km. What is its diameter?
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Q. 26. Define contact potential. Give its relation to the work function.
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Q. 27. If a copper wire is stretched to make 0.1 % longer, how will its resistance change?
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Q. 28. is desired to operate a 100 W, 120 V lamp at its current on 240 V—50 Hz supply. Give details how it could be done using: (i) a resistor (II) a capacitor (ii) a coil of 10 Ω, resistance and inductance.
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Q. 29. What is the resolving power of a lens? Explain Rayleigh’s Criterion. A telescope is used to observe two distant points 1 m part. The wavelength of light may be taken as 5000 A. The objective of the telescope is covered with a slit of 1 mm width. At what maximum distance the two sources can be distinguished?
What is the effect of decreasing the width of slit?
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Q. 30. How (i) AND gate is realised using NAND gate (ii) OR gate is realised using NAND gate (iii) NOT gate is realised using NAND gate.
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