JAMB and WAEC Physics questions: Magnets and magnetic fields

21 questions with answers and explanations. Tap an option to check yourself.

1. Question 1· Magnets and magnetic fields· JAMB

   Soft iron is used in electromagnets because it

   • Akeeps its magnetism permanently
   • Bis easily magnetised and demagnetised
   • Cis non-magnetic
   • Ddoes not conduct

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   Explanation and discussion

2. Question 2· Magnets and magnetic fields· WAEC

   Which of the following materials is strongly attracted by a magnet?

   • AIron
   • BCopper
   • CAluminium
   • DBrass

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   Explanation and discussion

3. Question 3· Magnets and magnetic fields· WAEC

   A bar magnet can be demagnetised by

   • Ahammering it while it lies east-west
   • Bstroking it with another magnet
   • Cplacing it in a solenoid carrying direct current
   • Dstoring it with keepers

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   Explanation and discussion

4. Question 4· Magnets and magnetic fields· JAMB

   At the magnetic equator, the angle of dip is

   • A90°
   • B0°
   • C45°
   • D180°

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   Explanation and discussion

5. Question 5· Magnets and magnetic fields· JAMB

   The north pole of a freely suspended magnet points approximately towards the Earth's

   • Aeast
   • Bgeographic south
   • Cgeographic north
   • Dwest

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   Explanation and discussion

6. Question 6· Magnets and magnetic fields· JAMB

   The angle of dip at the magnetic equator is

   • A0°
   • B90°
   • C45°
   • D180°

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   Explanation and discussion

7. Question 7· Magnets and magnetic fields· JAMB

   The magnetic field round a straight current-carrying wire consists of

   • Ano field at all
   • Bstraight lines parallel to the wire
   • Cradial lines from the wire
   • Dconcentric circles round the wire

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   Explanation and discussion

8. Question 8· Magnets and magnetic fields· JAMB

   The best way to demagnetise a bar magnet is to

   • Akeep it with keepers
   • Bplace it in a solenoid carrying direct current
   • Cstroke it with another magnet
   • Dplace it in a solenoid carrying alternating current and slowly withdraw it

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   Explanation and discussion

9. Question 9· Magnets and magnetic fields· JAMB

   The angle between the geographic meridian and the magnetic meridian is called the

   • Aangle of inclination
   • Bangle of dip
   • Cangle of declination
   • Dcritical angle

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   Explanation and discussion

10. Question 10· Magnets and magnetic fields· WAEC

    Which of these is a magnetic material?

    • Aaluminium
    • Bcopper
    • Cnickel
    • Dbrass

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    Explanation and discussion

11. Question 11· Magnets and magnetic fields· JAMB

    Outside a bar magnet, magnetic field lines run from

    • Athe north pole to the south pole
    • Bthe south pole to the north pole
    • Cthe middle to the ends
    • Dnowhere; there are no field lines

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    Explanation and discussion

12. Question 12· Magnets and magnetic fields· WAEC

    The angle between the magnetic meridian and the geographic meridian is called the

    • Adip
    • Bdeclination
    • Cinclination
    • Ddeviation

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    Explanation and discussion

13. Question 13· Magnets and magnetic fields· WAEC

    A magnet is best demagnetised by

    • Awithdrawing it slowly from a solenoid carrying alternating current
    • Bplacing it in a north–south direction
    • Cstoring it with keepers
    • Dcooling it

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    Explanation and discussion

14. Question 14· Magnets and magnetic fields· JAMB

    Soft iron is used as the core of an electromagnet because it

    • Ais easily magnetised and demagnetised
    • Bkeeps its magnetism permanently
    • Cis a good conductor of heat
    • Dis very hard

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15. Question 15· Magnets and magnetic fields· JAMB

    Which group of metals is strongly magnetic?

    • Asilver, sodium and calcium
    • Bcopper, zinc and tin
    • Caluminium, lead and gold
    • Diron, nickel and cobalt

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    Explanation and discussion

16. Question 16· Magnets and magnetic fields· WAEC

    The angle between the magnetic and geographic meridians is the

    • Aangle of incidence
    • Bangle of dip
    • Ccritical angle
    • Dangle of declination

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    Explanation and discussion

17. Question 17· Magnets and magnetic fields· WAEC

    Soft iron keepers are placed across the poles of stored bar magnets to

    • Areverse their poles
    • Bmake them stronger permanently
    • Cprevent them losing their magnetism
    • Dmake them lighter

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    Explanation and discussion

18. Question 18· Magnets and magnetic fields· JAMB

    Soft iron keepers are placed across the poles of stored magnets in order to

    • Areverse the poles
    • Bincrease their weight
    • Cmake them magnetic
    • Dprevent self-demagnetisation

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    Explanation and discussion

19. Question 19· Magnets and magnetic fields· JAMB

    A neutral point in a magnetic field is a point where

    • Aonly the Earth's field acts
    • Bthe field is strongest
    • Cthe resultant magnetic field is zero
    • Dthe needle points north

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    Explanation and discussion

20. Question 20· Magnets and magnetic fields· WAEC

    Iron filings sprinkled around a bar magnet gather most thickly at

    • Athe poles
    • Bthe middle of the magnet
    • Cplaces far from the magnet
    • Done side only

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    Explanation and discussion