Physics
Figure given below shows a bar magnet placed on the table top with it's north pole pointing towards south. The arrow shows the north-south direction. There are no other magnets or magnetic material nearby.
(a) Insert two magnetic field lines on either side of the magnet using arrow head to show the direction of each field line.
(b) Indicate by crosses, the likely positions of the neutral points.
(c) What is the magnitude of the magnetic field at each neutral point? Give a reason for your answer.
Answer
(a) The magnetic field lines for the magnet are as shown below:
(b) The likely position of the neutral points is indicated by crosses in the diagram below:
(c) The magnitude of magnetic field at each neutral point is zero because at these points the magnetic field of the magnet and the magnitude of the earth's horizontal magnetic field are equal in magnitude but in opposite directions such that the two fields neutralize each other.
Related Questions
You are provided with two similar bars, one is a magnet and the other is a soft iron bar. How will you distinguish between them without the use of any other magnet or bar?
[Hint: A magnet when suspended freely will rest only in north-south direction, but soft iron bar will rest in any direction]
A small magnet is suspended by a silk thread from a rigid support such that the magnet can freely swing. How will it rest? Draw a diagram to show it.
(a) Draw the pattern of magnetic field lines near a bar magnet placed with it's north pole pointing towards the geographic north. Indicate the position of neutral points by marking x.
(b) State whether the magnetic field lines in part (a) represent a uniform magnetic field or non-uniform magnetic field?
Explain what do you understand by magnetic induction. What role does it play in attraction of a piece of iron by a magnet?