Advertisements
Advertisements
Question
Write a note on the 'magnetic field'.
Advertisements
Solution
The magnetic field is defined as the region around a magnet where the magnetic force can be experienced by an object. Magnetic field lines are the geometrical representation of the magnetic field. Following are the characteristics of magnetic field lines:
- Magnetic field lines emanate from the North Pole and terminate at the South Pole of a magnet (outside the magnet).
- The degree of closeness of magnetic field lines represents the relative strength of the magnet.
- No two field lines can intersect each other.
Field lines due to a bar magnet are shown below:

Magnetic field lines due to a bar magnet.
RELATED QUESTIONS
You are given the magnetic field pattern of a magnet. How will you find out from it where the magnetic field is the strongest?
The wire in Figure below is being moved downwards through the magnetic field so as to produce induced current.
(a) moving the wire at a higher speed?
(b) moving the wire upwards rather than downwards?
(c) using a stronger magnet?
(d) holding the wire still in the magnetic field?
(e) moving the wire parallel to the magnetic field lines?
What is an artificial magnet? State two reasons why do we need artificial magnets .
What do you understand by the term magnetic field lines?
Explain why iron filings which are sprinkled on a sheet of cardboard placed over a bar magnet take up a definite pattern when cardboard is slightly tapped.
Figure. shows a bar magnet placed on the table top with its north pole pointing towards south. The arrow shows the north-south direction. There are no other magnets or magnetic materials nearby.

Indicate by crosses, the likely positions of the neutral points.
How do you account for the following fact?
Soft iron keepers help to prevent the magnets from losing their magnetic properties.
Complete the following diagram of magnets to show the lines of force.

Define magnetic field lines of force.
A student fixes a white sheet of paper on a drawing board. He places a bar magnet in the centre and sprinkles some iron filings uniformly around the bar magnet. Then he taps gently and observes that iron filings arrange themselves in a certain pattern.
- Why do iron filings arrange themselves in a particular pattern?
- Which physical quantity is indicated by the pattern of field lines around the bar magnet?
- State any two properties of magnetic field lines.
