Question

Draw the pattern of arrangement of the iron filings when current is passed through the loop:
          

Answer 1

Hint:First, we draw the diagram showing the position and direction of the current in the plane. Then use the right-hand rule i.e. if the thumb of the right hand denotes the direction of the current then the curled fingers shows the direction of the magnetic field. Using superposition principle net effect of the current carrying wires can be estimated.

Complete Step by Step Solution:
As per the given circuit, first draw the direction of the current. The direction of the current is from positive to negative as the ‘cross’ and ‘dot’ denote the directions of current as out of the plane and into the plane respectively. From the figure given in question, it is clear that the current will come out of the plane from point M and will move into the plane at point N.

Now, using the right-hand rule we will know the direction and alignment of the iron filings on the plane.
Right hand thumb rule states that if the thumb of the right hand is pointed along the direction of current, then the remaining fingers of the same hand at the right angled position indicate the direction of the magnetic field due to current. So, the iron filling spills in the circular form as shown in the figure.

Consider the pattern of arrangement of the iron filings when current is passed through the loop,
     

Note:The magnetic field lines are circular for a single connecting wire. But in the given case there are two sources. Thus, the net effect on any particle in the plane will be equal to the linear sum of the effect of each wire and thus it will be elliptical.