Question

8. Draw a diagram to show the magnetic field lines around a bar magnet.
9. What is a magnetic field ? How can the direction of magnetic field lines at a place be determined ?
10. Explain why, two magnetic field lines do not intersect each other.
11. When an electric current is passed through any wire, a magnetic field is produced around it. Then why an
electric iron connecting cable does not attract nearby iron objects when electric current is switched on through
it?​

Answer 1

8. Refer to the attachment.

9. Magnetic field is the region around a magnet or a current carrying wire, where magnetic substances like iron, nickle and cobalt may experience some force.

The direction of magnetic field lines at a place be determined by drawing a tangent to the magnetic field at that particular point.

Also, there are some rules like Right Hand Thumb Rule, Maxwell's Corkscrew rule etc to determine the direction of magnetic field.

10. Two magnetic fields can never intersect each other because, if there exists a point where the magnetic field's lines of force intersect, it will mean that when a magnetic compass is kept at that point, the compass' needle will point at two N-S directions at the same time. But, this is not possible. Hence, two magnetic field lines never intersect each other.

11. An electric iron connecting cable does not attract nearby iron objects when electric current is switched on through  it because the magnetic field produced by it is very weak.

Answer 2

Answer:

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i) Two magnetic field lines never interest each other.

ii) Outside the magnet, the magnetic field lines are directed from North pole of the magnet towards the South pole.

iii) The magnetic field lines at any one point give the direction of magnetic field at that point .