To study the phenomenon of electromagnetic induction.
The phenomenon of electromagnetic induction is the existence of an induced current in a circuit (such as a coil) placed in a region where the magnetic field motion changes with the time. The magnetic field may change due to relative motion between coil and magnet placed near the coil as shown in the Fig. 1. We know that a current-carrying conductor also produces magnetic field that changes with a change in the current flowing through it. Thus if a coil is placed near to a current-carring conductor, an induced current in the coil may setup due to a change in the current through the current-carrying conductor.
Fig. 1: Moving a magnet towards a coil sets up a current in the coil circuit,
as indicated by deflection in the galvanometer needle.
As performed in the real lab:
Magnetic bar, a galvanometer, coil and connecting wires.
- Take a coil of wire having a large number of turns.
- Connect the end of the coil to a galvanometer.
- Take a strong bar magnet and move its north pole into the coil and observe the changes in the galvanometer needle.
- Repeat earlier step with the south pole of the bar magnet.
- Now repeat the procedure with the coil having a different number of turns and the variation in the deflection of the galvanometer needle.
As performed in the simulator:
- Click on any one magnet from Bar magnets section.
- Drag the bar magnet in/out of the Coil and observe the deflection of needle in the Galvanometer.
- Repeat the same procedure for other bar magnet.
- For each magnet, observe the direction of deflection and change in deflection when we move magnet in/out with varying speeds.
- Click on Next to continue.
- Again, click on any one magnet from Bar magnets section.
- From the Number of turns section select the number of turns in the coil.
- Drag the bar magnet in/out of the coil and observe the change in deflection for different number of turns in Coil.
- Repeat procedure for all options in Number of turns. After this Observations & Inference will be displayed.
- Note the observations and inference.
Observations & Inference:
- When we move the magnet in or out of the coil, the needle of galvanometer gets deflected in different directions.
- When we insert the north pole (N) of bar magnet into the coil, the needle gets deflected in negative direction.
- When we insert the south pole (S) of bar magnet into the coil, the needle gets deflected in positive direction.
- When we move the bar magnet in or out of the coil with varying speed, the speed of deflection changes accordingly.
- As we increase the number of turns in the coil, the deflection increases.
- The deflection of galvanometer needle indicates the presence of current in the coil.
- The direction of deflection gives the direction of flow of current.
- The speed of deflection gives the rate at which the current is induced.
- The deflection in galvanometer changes with the change in number of turns in the coil - more the number of turns in the coil greater is the deflection.