MCQs | Chapter 8 | Magnetism | 9th Physics | National Book Foundation | Federal Board

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(i) If a bar magnet is cut in half it will become
(a) a monopole (b) unmagnetized (c) the same magnet (d) magnet of less strength
(ii) Which one is the quickest method to magnetize a material?
(a) strike with hammer (b) moving into magnetic field
(c) stroking the opposite pole (d) putting inside a current carrying coil
(iii) Earth’s magnetic field intensity is:
(a) constant everywhere (b) very high at equator (c) very low at poles (d) varies place to place
(iv) The cause of the Earth’s magnetic field is:
(a) rotational motion of Earth (b) spinning of Earth
(c) pull of the Sun (d) motion of ions in the core
(v) Material which is the best one for making a permanent magnet:
(a) soft iron (b) nickel (c) cobalt (d) steel
(vi) Material which is the best one for making an electromagnet:
(a) soft iron (b) nickel (c) cobalt (d) steel
(vii) A sensitive magnetic material is to shielded by the external magnetic field. It should be kept inside a box of:
(a) wood (b) plastic (c) steel (d) soft iron
(viii) Magnetic field lines:
(a) are farthest at poles (b) intersect each other (c) are closed (d) don’t past in vacuum
(ix) When two current carrying wires in the same direction are placed parallel near each other, due to magnetic field produced by each wire they:
(a) repel each other (b) attract each other
(c) have no effect on each other (d) stop moving the current through them
(x) Which of the following material is ferromagnetic?
(a) silver (b) copper (c) aluminum (d) nickel
(i) Can two magnetic field lines intersect each other? Justify your answer
(ii) A freely suspended magnet always points along north-south direction. Why?
(iii) What is the neutral zone or field free region of the magnetic field?
(iv) Is there any material which does not have any magnetic behavior? Justify your answer.
(v) A proton is also a charged particle and spins like an electron. Why its effect is neglected in study of magnetism?
(vi) What is the geomagnetic reversal phenomenon? Explain.
(vii) Why the Earth spins about its geographical axis instead of its magnetic axis? Explain
(viii) Why the Earth’s geographical and magnetic axis are not coincident? Explain.
(ix) What is the difference between paramagnetic and ferromagnetic materials?
(x) At what factors the strength of the magnetic field of an electromagnet depends?
(xi) Draw magnetic field lines of two solenoids placed near each other i) facing same poles to each other ii) facing opposite poles to each other.
1. Find the magnetic field due to a wire at 10cm, if 1.3A current is passing through the wire.