Advertisements
Advertisements
प्रश्न
Describe two methods of determining the arrangement of the lines of force in the field close to a bar magnet. Give a brief explanation of each method.
Advertisements
उत्तर
First method: Place cardboard on the top of a bar magnet and scatter some iron filings uniformly over the whole of cardboard. Now tap it with a pencil. The filing is magnetized by induction and arrange themselves in curved lines as shown in the figure. The curved lines are called the magnetic lines of force which may be defined as the lines in a magnetic field along which free magnetic poles tend to be driven if free to do so.
Second method: Lines of force can be traced on a paper by using a tracing needle or small magnetic compass needle.
The bar magnet is placed on a sheet of paper and its boundary is drawn with a sharp pencil. A point X is marked along the boundary towards the north of the magnet.
The tracing needle is then placed at point X in such a way that its one endpoints towards the point X. With the help of a pencil, the direction of the other end of the needle is marked on paper. Let it be point Y.
Now, shift the needle from the point X and place it in such a way that its one end points towards the point Y. The direction of other end of needle is marked by pencil. Let it be point Z. The process is continued till a closed curve is obtained.
This curve is called a magnetic line of force.
If we plot a number of such curves around the magnet, starting from different points then space so enclosed is called magnetic field.
APPEARS IN
संबंधित प्रश्न
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 magnetic field lines produced by a bar magnet:
(a) originate from the south pole and end at its north pole
(b) originate from the north pole and end at its east pole
(c) originate from the north pole and end at its south pole
(d) originate from the south pole and end at its west pole
The magnetic field lines:
(a) intersect at right angles to one another
(b) interest at an angle 45° to each another
(c) do not cross one another
(d) cross at an angle of 60° to one anotherv
Which of the following statements is incorrect regarding magnetic field lines?
(a) The direction of magnetic field at a point is taken to be the direction in which the north pole a magnetic compass needle points.
(b) Magnetic field lines are closed curves.
(c) If magnetic field lines are parallel and equidistant, they represent zero field strength.
(d) Relative strength of magnetic field is shown by the degree of closeness of the field lines.
In the straight wire A, current is flowing in the vertically downwards direction whereas in wire B the current is flowing in the vertically upward direction. What is the direction of magnetic field:
(a) in wire A?
(b) in wire B?
Name the rule which you have used to get the answer.
What is a lodestone?
Explain what you understand by magnetic induction. What role does it play in attraction of a piece of iron by a magnet?
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.
What conclusion is drawn regarding the magnetic field at a point if a compass needle at that point rests in any direction? Give reason for your answer.
The magnetic field is the strongest at ____________.
