MAGNETICDIVER

By D N VASISHTClass 12 ABOARD Roll no.-

CERTIFICATE

This is to certify that the PHYSICS project titled MAGNETIC DIVER has been successfully completed by DN VASISHT of Class XII in partial fulfillment of curriculum of CENTRAL BOARD OF SECONDARY EDUCATION (CBSE) leading to the award of annual examination of the year 2014-2015.

INTERNAL EXAMINER TEACHER IN CHARGE

ACKNOWLEDGEMENT

It gives me great pleasure to express my gratitude towards our Physics teacher MRS PRAGYA NOPANY for her guidance, support and encouragement throughout the duration of the project. Without her motivation and help the successful completion of this project would not have been possible.

DN VASISHT

AIMTo investigate and understand the working of a magnetic diver by studying induction in a test tube.

APPARATUS

Following is the apparatus for the investigation- 30m coil Test tube Iron nail Styrofoam ball 3V Battery

SCHEMATIC DIAGRAMS

INTRODUCTIONElectromagnetic induction is the production of an electromotive force across a conductor when it is exposed to a varying magnetic field. It is described mathematically by Faraday's law of induction, named after Michael Faraday who is generally credited with the discovery of induction in 1831.Faraday's law of inductionFaraday's law of induction is a basic law of electromagnetism predicting how a magnetic field will interact with an electric circuit to produce an electromotive force (EMF)a phenomenon called electromagnetic induction. It is the fundamental operating principle of transformers, inductors, and many types of electrical motors, generators and solenoidsThe most widespread version of Faraday's law states:The induced electromotive force in any closed circuit is equal to the negative of the time rate of change of the magnetic flux enclosed by the circuit.Faraday's law states that the EMF is also given by the rate of change of the magnetic flux:

LENZ LAW

Lenz's law is named after Heinrich Lenz, and it says:An induced electromotive force (emf) always gives rise to a current whose magnetic field opposes the original change in magnetic flux.

Lenz's law is shown with the negative sign in Faraday's law of induction:

This indicates that the induced emf () and the change in magnetic flux (B) have opposite signs. As such it is a qualitative law that refers to the direction of induced current and its magnetic field without quantitatively defining their magnitudes.PROCEDURE Stand a test tube with water on a rubber base. Wind 30 m of insulated copper wire. Poke a paper pin in a Styrofoam ball. The ballAnd pin must just float in water. Scrape the insulation from the ends of the coil and attach them to a 1.5-volt battery.OBSERVATIONSEXPERIMENTOBSERVATIONS

Connected the battery to the coil.The coil will become an electro-magnet and the pin-ball will take a deep dive

Disconnected the battery.The pin will rise up.

DISCUSSION ON OBSERVATION

When the coil is connected to the battery, a current flows through it which generates a magnetic field. The coil acts like a solenoid and the iron nail behaves like an electromagnet. There is uniform magnetic field inside the solenoid and at the mouth of the solenoid there is magnetic field of lesser magnitude. Due to this the iron nail experiences a net force downwards and hence dips into the water. But when the battery is removed, the magnetic field disappears and the iron loses it magnetism and the nail pops up.

CONCLUSIONForm the above experiment we can see that the phenomenon of electromagnetic induction can be used to demonstrate various experiments. In this experiment we can see the phenomenon of electromagnetic induction is responsible for making the iron nail dip into the water.

PRECAUTIONS Coil should be cleaned with sandpaper and insulation should be removed. Remove the battery when not in use. Ensure that the nail floats in water.

SOURCES OF ERROR The nail may be very light and hence does not go into the water. The coil may not be wounded properly around the test tube.

BIBLIOGRAPHY

http://www.arvindguptatoys.com/arvindgupta/toys/pdf/ttinducdoit.pdf http://en.wikipedia.org/wiki/Lenz%27s_law http://en.wikipedia.org/wiki/Faraday%27s_law_of_induction http://en.wikipedia.org/wiki/Electromagnetic_induction

EXPERIMENT PHOTOS

SUGGESTIONS FOR FURTHER ACTIVITY

The activity can be improvised by using different liquids in the test tube and finding out the extent to which the nails dips in the water.