Describe an activity to 1) demonstrate the pattern of magnetic field lines around a straight conductor carrying current and 2) find the direction of the magnetic field produced for a given direction of current in a conductor. Answer has not been uploaded for this question even though it says that it has been answered

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Let us take a cardboard and insert a thick straight copper wire at centre of cardboard.

Let us maje sure copper wire is fixed tightly and it is not loose to go down.

Let us connect the two ends of copper to a battery through a rheostat and key.

Let us sprinkle some iron filings on cardboard and close the key so that some current is passed

through the wire i9nserted in the cardboard. Let us gently tap the cardboard and we see that

a circular pattern of iron filings is formed on the card board. This pattern represents the magnetic field lines.

 

To find the direction of magnetic field lines, let us place a magnetic compass on a point on the circular lines,

say at a point P as shown in figure. Magnetic compass needle will show the direction of magnetic field which

is in the direction of tangent of circle.

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To get the direction of magnetic field due to current carrying wire, let us apply the Right hand thumb rule.

 

If the current carrying wire is held in the right hand so that thumb is pointed in the direction of current as shown in figure,

then curling of fingers gives the direction of megnetic field.

 

This is known as right hand thumb rule