: CBSE Sample Question Papers

[Derivation Type Questions-3 Marks Questions]

1. Classify materials on the basis of their behaviour in a magnetic field. Under which category does iron come ? How does the magnetic property of iron change with temperature ?
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2. A short bar magnet of magnetic moment 0.9 JT^-1 placed with an axis 45° with uniform external magnetic field experiences ‘a torque of magnitude 0.063 J. Find the strength of the magnetic field.
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3. State tangent law. How will the reduction factor of a tangent galvanometer change when the number of turns of its coil is doubled ? Explain.
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4. Name the three elements of earth’s magnetic field. Represent them graphically. How all elements are related to each other ?
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5. The value of dip at a place is δ₁ and at a plane normal to the first is δ₂. Show that the true value of angle of dip δ is related to δ₁ and δ₂ as

cot² δ = cot² δ ₁ + Cot² δ ₂
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6. Derive the relation for P.E. of a dipole placed in uniform magnetic field. When is P.E. equal to zero ?
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7. How an atom can act as dipole ? Determine dipole moment of an atom consisting of only one electron.
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8. What is the cause of earths magnetic field ?
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9. How can magnetic moment of two magnets be compared by sum and difference method ?
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10. Compare the properties of para, dia and ferro magnetic substance.
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11. Draw Hysteresis curve. What is its use in actual life ?
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12. What is Domain theory of ferromagnetic substances ?
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13. Give Curies’law in magnetism.
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14. An iron rod of volume 10^-4 m³ and relative permeability 1000 is placed inside a long solenoid wound with 5 turns per cm. If a current of 0.5 A is passed through the solenoid, find magnetic moment of the rod.
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15. Determine a relation for torque acting on a dipole placed in a uniform magnetic field.
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Long Answer Type Question

Q. 1. (a) What is the evidence that the earth has magnetic field ? What is the order of its magnitude ?
(b) Define magnetic axis, Geographic axis, magnetic meridian and Geographical meridian.
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Q. 2. Name and define element of earth’s magnetism ?
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Q. 3. If δ₁ and δ₂ he the apparent value of dip observed in two planes at right angles to each other and δ is the true angle of dip, prove that

cot² δ1 + cos² δ2 - cot² δ

OR
How can the angle of dip be determined without placing the dip circle in magnetic meridian?
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Q. 4. Compare moving magnet type galvanometer with moving coil galvanometer. Which one is preferred ?
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