: CBSE Sample Question Papers

DELHI

Q. 1. Horizontal component of earth’s magnetic filed at a place is V3 times the vertical component. What is the value of dip at this place ?
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Q. 2. Force between two electric charges kept at a distance d apart in air is F. If these charges are kept at same distance in water, how does the force between them changes ? 1
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Q. 3. Give two factors on which the thermo e.m.f. produced in thermocouple depends.
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Q. 4. An electric current in the direction B to A is decreasing. What is the direction of induced current in the metallic loop kept above the wire as shown in the figure.
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Q. 5. Name the electromagnetic radiations used for viewing objects through haze and fog. I
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Q. 6. Give the ratio of number of holes and the number of conduction electrons in an instrinsic semiconductor. 1
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Q. 7. In the given diagram, is the diode D forward or reverse biased ? I
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Q. 8. Name the planet which has maximum value of albedo.
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Q. 9. Two charges of unknown magnitude and sign are placed a distance d apart. The electric intensity is zero at a point, not between the charges but on the line joining them. Write two essential conditions for this to happen.
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Q. 10. The variation of potential difference V with length I in case of two potentiometers X and Y is shown in the given diagram. Which one of these two will you prefer for comparing e.m.f.s of the two cells and why ?
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Q. 11. Name any one material having a small value of temperature coefficient of resistance. Write one use of this material.
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Q. 12. Write down two advantages and two disadvantages of a secondary cell over a primary cell.
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Q. 13. In figure, the straight wire AB is fixed while the loop is free to move under the influence of electric current flowing in them. In which direction does the loop begin to move ? Give reasons for your answer.
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Q. 14. A radio frequency choke is air-cored coil whereas an audio frequency choke is iron-cored. Give reasons for the difference.
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Q. 15. An astronomical telescope consists of two lenses set 36 cm apart and have magnifying power of 8. Calculate the focal length of the lenses.
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Delhi

Q. 1. Name the physical quantity whose S.I. unit is coulomb/volt.
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Q. 2. Write the frequency limit of visible range of electromagnetic spectrum in k Hz.
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Q. 3. How does the conductance of semiconducting material change with the rise in Temperature ?
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Q. 4. The force F experienced by a particle of charge e moving with velocity v in a magnetic field B is given by

Of these, name the pairs of vectors which are always at right angles to each other. 1
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Q. 5. Two wires A and B are of same metal, have the same area of cross-section and have their lengths in the ratio 2 : 1. What will be the ratio of currents flowing through them respectively the same potential difference is applied across length of each of them ?
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Q. 6. Calculate the rms value of alternating current shown in the figure.
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Q. 7. The image of an object formed on the screen is not in sharp focus. Suggest a method to get clear focussing of the image on the screen without disturbing the position of the object, the lens or the screen.
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Q. 8. Two protons A and B are placed between two parallel plates have potential difference V as shown in figure. Will the proton experience equal or unequal force ?
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Q. 9, Define the terms threshold frequency and stopping potential for photoelectric effect. Show graphically how the stopping potential for a given metal varies with frequency of the incident radiation, Mark threshold frequency on the graph.
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Q. 10. Draw a labelled diagram of Laclenche cell. Write down the function of charcoal powder and manganese dioxide used in porous pot.
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Q. 11. How does the mutual inductance of a pair of coils changes when (i) Distance between the coil is increased ? (ii) the number of turns in each coil is decreased ? 2
Justify your answer in each case.
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Q. 12. Define the terms magnetic inclination and horizontal component of earth’s magnetic field at a place. Establish the relationship between the two with the help of a diagram.
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Q. 13. An electron in an atom revolves around the nucleus in an orbit of radius 0.53 A. Calculate the equivalent magnetic moment if the frequency of revolution of electron is 68 X 10 MHz.
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Q. 14. Write the function of base region of a transistor. Why is this region made thin and slightly doped ?
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Q. 15. Derive an expression for the energy stored in a parallel plate capacitor with air as the medium between the plates.
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