Magnetic effects of electric currents,a compass needle gets deflected,magnetic fields lines are closed curves,magnetic field

 

 

          Magnetic effects of electric currents

 

 

 

Why does a compass needle gets deflected when brought near a current carrying conductor?

A compass needle gets deflected when brought near a current carrying conductor because an electric current carrying wire produce magnetic field around it.

We can illustrate this with the such example

We take a straight copper wire and place this copper wire between the points (X and Y). in the electric circuit.

The wire is kept perpendicular to the plane of the paper. Also a compass is kept near horizontally to the copper wire.

And when circuit is completed , then current is passed through this circuit. And found that compass needle gets deflected. It means to say that there is magnetic field produced when electric current is passing through the copper wire.

                          X

                         Y

 

 

 

 

Why does a compass needle gets deflected when brought near a magnetic bar ?

 

Bar magnet:--

 

Bar magnet is small bar magnet , which is rectangular piece of a object and having s compass needle.

It has permanent magnetic properties.  It has two poles.

(1) North pole

(2) South pole

North pole :--

The ends of the compass needle pointing towards the north direction is called north pole.

South pole:--

The ends of the compass needle pointing towards the south direction is called south pole.

 

Magnetic field:--

The magnetic field is a field generated electric charge or magnet in the motion.

A magnetic field is a region surrounding a magnet , in which the force of the magnet can be deflected.

The magnetic field can be represented by the magnetic field lines.

 

 

 

 

why magnetic fields lines are closed curves?

A magnetic field is a region surrounding a magnet , in which the force of the magnet can be deflected.

Magnetic field is that quantity that has both direction and magnitude.

The direction can be easily found by compass needle.

The direction of the magnetic field is to be the direction in which the north pole of the compass needle moves inside it.

Thus , the field lines emerge from north pole and merge at the south pole. But inside the magnet , the direction of the field lines is from south pole to north pole. Thus , the magnetic field lines are closed curves.

 

 

 

Important point :--

 

·       The relative strength of the magnetic field is shown by the degree of the closeness of the field lines.

·       The magnetic field is stronger near the pole ends.

·       No two field lines are found to cross each other.