..  4.7

Electromagnetic induction
=========================

**Objective**

Explore the voltage induced across a coil by a changing magnetic field,
by dropping a small cylindrical magnet into a coil. Use a tube to guide
the magnet through the coil.

.. image:: schematics/induction.svg
	   :width: 300px
.. image:: pics/induction-screen.png
	   :width: 300px

**Procedure**

-  Click on Start Scanning. A horizontal trace should appear
-  Drop the magnet through the coil, until a trace is caught.
-  Repeat the process by changing the parameters like magnet strength,
   speed etc.

**Discussion**

The result is shown in figure. The amplitude increases with the speed of
the magnet. From the graph, we can find the time taken by the magnet to
travel through the coil.

The second peak is bigger than the first peak. Why ? Where will be the
magnet at the zero crossing of the induced voltage? Drop the magnet from
different heights and plot the voltage vs square root of the height.
