CBSE Physics Sample Question Paper : Set-9
Q. 1. Mention two defects of a simple cell.
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Q. 2. When are the voltage and current in a LCR series A.C. circuit in phase?
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Q. 3. Why cannot two magnetic lines of forces due to a bar magnet cross each other? .
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Q. 4. The magnetic flux threading a coil changes from 12 X 10-3 Wb to 7 X 10-3 Wb in 0.01 s. Calculate the induced e.m.f.
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Q. 5. What are comets composed of?
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Q. 6. Suppose planet goes around the sun twice as fast as earth what will be its orbit size as compared to that of the earth?
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Q. 7. What oscillates in electromagnetic waves? Are these waves transverse or longitudinal 7
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Q. 8. Write the relationship between amplitudes of electric and mag¬netic fields in free space for an electromagnetic wave,
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Q. 9. Explain how the conductivity of an electrolyte increases with the concentration of the ions and their mobility.
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Q. 10. Define elliptically polarised light.
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Q. 11. What should be the minimum energy of electron exciting the hydrogen atom so that three spectral lines are excited?
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Q. 12. How can you produce dispersion without deviation?
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Q. 13. Calculate the Binding energy per nucleon of 4020Ca nucleus, (mass of 4020Ca = 39.96259 amu, mass of neutron 1.00866 amu, mass of proton 1.00782 amu).
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Q. 14. When an A.C. circuit with L, C and R in series is brought into resonance, the current has large value, why? If the capacitance of C is increased, will the current increase or decrease? Explain with suitable relation.
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Q. 15. Why it is necessary to use small wavelengths of light to increase the resolving power of a microscope?
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Q. 16. The value of solar constant at the surface of the earth is 1400 Wm-2. Compute its value at Jupiter which is 5.2 AU from the sun.
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Q. 17. Prove that the induced charge does not depend upon the rate of change of flux.
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Q. 18. A nucleus nX emits one α-particle and one β-particle. What are the mass number and the atomic number of the product nucleus?
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Q. 19. An oil drop carries six electronic charge has a mass of 1.6 x 10 gram and falls with a terminal velocity in air. What magnitude of vertical electric field is required to make the drop move upwards with the same speed as it was formally moving downward?
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Q. 20. What is the principle of vibration magnetometer?
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Q. 21. Distinguish between intrinsic and extrinsic semiconductors.
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Q. 22. Show, by drawing ray diagrams, how a totally reflecting glass prism can be used to deviate a ray of light through (0 90 ° (ii) 180°.
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Q. 23. Calculate the magnetic force acting on a closed loop carrying a current placed in a uniform magnetic field B?
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Q. 24. If the distance of any one of the planets from the sun is known, how can the distance of any other planet be calculated?
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Q. 25. Show that the trajectory of an electron entering perpendicularly in a uniform electric field is a parabola.
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Q. 26. Obtain an expression for the force between infinitely long straight line conductors parallel to each other. Hence define one ampere.
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Q. 27. Derive a formula for combined focal length of two thin convex lenses in contact.
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Q. 28. What are Eddy currents? How are these produced? Give one application.
Explain with necessary theory how will you compare the intensity of illumination of two sources of light using B usen’s grease spot photometer.
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Q- 29. (a) What is the importance of power factor?
(b) An electric bulb of 200 W, 240 V is joined in series with an inductance 0.15 H and * capacitor at 220 V. What is the capacitance if the active power in the circuit is half of the total power? What is the current in the circuit?
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Q. 30. A sinusoidal emf is applied to a circuit containing a capacitor only. Show that current leads the voltage by π /2.
Find the maximum value of current when an inductance of one henry is connected to an a.c. source of 200 volts, 50 Hz.
Derive an expression for the instantaneous value of the induced emf in a coil when it is rotated in a uniform magnetic field at a uniform angular velocity. How does the emf vary when the coil rotates through an angle of 2 π?
What is the instantaneous value of induced emf when the plane of the coil makes an angle of 60° with the magnetic lines?
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