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WORKSHEET 1(Magnetism and matter)



               1)A bar magnet AB with magnetic moment M is cut into two equal parts perpendicular to its axis. One
               part is kept over the other so that end B is exactly over A. What will be the magnetic moment of the
               combination so formed?


               (a)zero                                    (b)M/4                                 (c)M                               (d)3M/4

               2)Two unlike magnetic poles of strength 10 A-m each are held in air at a distance of 0.10 m from each
               other. What is the magnetic force of attraction between them?

                      -3
                                             -3
                                                                                        -3
                                                                     -3
               (a)3x10  N                       (b)2.5x10  N                         (c)1.5x10  N                  (d)1x10  N
               3)SI unit of magnetic dipole moment is
                                                                                         2
                                           2
               (a)A/m                              (b)A-m                                        (c)volt/meter            (d)A/m
               4) We can determine the sense of magnetic field lines surrounding a straight current carrying
               conductor by applying ________________rule.

               5) The magnetic field strength at a point due to a short bar on its axis varies____________as
               cube of distance of the point from the centre of magnet.


               6) Inside the body of magnet the direction of magnetic field lines is from_______________.

               7)  Why is a current loop considered a magnetic dipole?

               8) A bar magnet is placed in a uniform magnetic field with its magnetic moment making an

               angle Ө with the field. (i) Write expressions for torque on the bar magnet and potential energy
               of magnet in this orientation. (ii) When is this energy minimum?

               9) What happens if a bar magnet is cut into two pieces (i) transverse to its length (ii) along its
               length?

               10) What is the surest test of magnetism? Justify.
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