With the help of a labelled diagram, describe an activity to illustrate the pattern of the magnetic field lines around a straight current carrying long conducting wire
Is there a similar magnetic field produced around a thin beam of moving (a)alpha particles (b)neurons. Justify your answer.

Dear student,

Magnetic field lines around a straight long current carrying conducting wire is is concentric circles whose direction can be determined by the Maxwell's Right-Hand-Thumb Rule.

Such questions are made for enhancing the self-creative skills and should be tried
answering on your own. However, here are a few points that will help you in framing
your answer:

1)Right-Hand-Thumb Rule: The rule states that if we imagine to hold a current carrying conductor in our right hand, thumb indicating the direction of the current, then the four fingers curled direction gives us the direction of magnetic field loop lines.

This rule has been depicted in the diagram given below:

2) In figure (a), the current is upward, thus magnetic field lines are in anticlockwise direction, whereas in figure (b), the current is downwards, thus magnetic field lines  shown by the curl of fingers is clockwise.
3) Now you can setup your own circuit with battery,rheostat, wire.and a switch Some iron fillings spread on a plane piece of cardboard can mimic the pattern of magnetic filed lines whose diagram is depicted below:

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answer. You can also send us your answers here for feedback and required corrections, if any.

Moving on to the next part:
Magnetic field lines pattern for a thin beam of moving:
(a) Alpha- particles: It produces similar magnetic field lines to the current carrying conductor as alpha - particles have positively charged particles and movement in thin beam makes it similar to a long current carrying conductor.
(b) Neutron : It has no charge on itself, thus its thin beam movement will not act as current carrying conductor. Thus no such magnetic filed lines will be produced.


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(i) The right-hand thumb rule.

(ii) Yes, α−particles being positively charged constitutes a current in the direction of motion.

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Dear student,

Apparatus: A battery (12 V), a variable resistance for a rheostat), an ammeter (0-5 A), a plug key, and a long straight thick copper wire. Procedure: Fix the cardboard and insert the wire through the centre of cardboard such that it is normal to its plane. Connect the wire with rheostat, ammeter, battery and plug key in series Sprinkle the iron filings uniformly on the cardboard. Keep the variable of the rheostat at a fixed position and note the current through the ammeter. Close the key and gently tap the cardboard. Observe the pattern of the iron filings over the cardboard.

The magnetic field lines are formed in concentric circles around the current carrying conductor and whose centre lies on the wire. These lines do not intersect each other and are equidistant from each other. 1. Right hand thumb rule II. Since alpha particles are positively charged so a magnetic field will be produced. But neutrons are neutral charge so no magnetic field is produced.

I hope this helps

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