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CERTIFICATE OF AUTHENCITY

THIS IS TO CERTIFY THAT MASTER NIKHIL DWIVEDI OF CLASS XII-A OF KENDRIYA VIDYALAYA ASC CENTER(S) HAS SUCCESSFULLY CARRIED OUT THE INVESTIGATORY PROJECT ENTITLED “TO DETERMINE EFFECT OF INCREASING TEMPERATURE ON STRENGTH OF MAGNET” UNDER THE SUPERVISION OF PHYSICS TEACHER MRS SELEENA JACKSON FOR THE ACADEMIC YEAR 2016-2017. ALL THE WORKS RELATED TO THE PROJECT IS DONE BY THE CANDIDATE HIMSELF. THE APPROACH TOWARDS THE SUBJECT HAS BEEN SINCERE AND SCIENTIFIC.

ROLL NO- DATE- Signature (Subject teacher) Signature (Examiner)

ACKNOWLEDGEMENT

I feel proud to present my Investigatory project in Physics on the topic “TO DETERMINE EFFECT OF INCREASING TEMPERATURE ON STRENGTH OF MAGNET”. This project wouldn’t have been feasible without the proper and rigorous guidance of my physics teacher who guided me throughout this project in every possible way. An investigatory project involves various difficult lab experiments which have to be carried out by the student to obtain the observations and conclude the report on a meaningful note. Rigorous hard work has been put in this project to ensure that it proves to be the best. I hope that this project will prove to be a breeding ground for the next generation of students and will guide them in every possible way.

INDEX Introduction Theory Experiment Aim Requirement Theory Procedure Observations

Result Bibliography

INTRODUCTION

A magnet is a material or objects that Produces magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets. A magnet is any object that produces a magnetic field. Some magnets, referred to as permanent, hold their magnetism without an external electric current. A magnet of this nature can be created by exposing a piece of metal containing iron to a number of situations (i.e. repeatedly jarring the metal, heating to high temperature). Soft magnets, on the other hand, are those that lose their magnetic charge properties over time. Additionally, paramagnetic objects are those that can become magnetic only when in the presence of an external magnetic field.

A magnetic field is the space surrounding a magnet in which magnetic force is exerted. The motion of negatively charged electrons in the magnet determines not only the polarity, but also the strength of the magnet (Cold magnet). Magnets are filled with magnetic lines of force. These lines originate at the north pole of the magnet and continue to the South Pole. The north pole is positive. Magnetic lines of force do not intersect one another. Magnetism is created by the alignment of small domains within a specific set of metal. These domains function as all atoms do, thus the temperature affects the movement. The higher the heat, the greater the energy, and as such the movement of the particles. In contrast, cold temperature slows the movement (magnetic Field Strength and Low Temperatures). Slower movement leads to more fixed directions in terms of the domains.

THEORY

A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets. A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator door. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic (or ferrimagnetic). These include iron, nickel, cobalt, some alloys of rare earth metals, and some naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all other substances respond weakly to a magnetic field, by one of several other types of magnetism. Ferromagnetic materials can be divided into magnetically "soft" materials like annealed iron, which can be magnetized but do not tend to stay magnetized, and magnetically "hard" materials, which do. Permanent magnets are made from "hard"

ferromagnetic materials such as alnico and ferrite that are subjected to special processing in a powerful magnetic field During manufacture, to align their internal microcrystalline structure, making them very hard to demagnetize. To demagnetize a saturated magnet, a certain magnetic field must be applied, and this threshold depends on coercivity of the respective material. "Hard" materials have high coercivity, whereas "soft" materials have low coercivity. The overall strength of a magnet is measured by its magnetic moment or, alternatively, the total magnetic flux it produces. The local strength of magnetism in a material is measured by its magnetization.

EXPERIMENT AIM

To determine the effect of increasing temperature on strength of magnet.

APPARATUS

• 1 permanent bar magnet • Tongs for magnet • Insulating container • Three strong bowls • Burner for heating or oven • Paper clips(1000)

THEORY

A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets. PROCEDURE 1. Paperclips were placed in a bowl. 2. The magnet was weighed and recorded. 3. The magnet was placed in oven set to highest temperature possible. 4. The magnet was allowed to reach the temperature of the oven. 5. The magnet was then placed in a bowl filled with paperclips. 6.The amount of paper clips attracted by the magnet was weighed and recorded. 7.The steps 5 and 6 were repeated after setting the oven at different temperatures and the quantity of paper clips attracted was weighed.

OBSERVATION

The weight of pins attracted by the magnet at different temperatures is:

Temperature (◦c) Weight (g) No of pins attracted by magnet

200 200 134 180 210 140 160 230 153 140 210 141 120 230 151 100 220 146 24 124 82

RESULT

The graph indicates that initially as the temperature decreases, the number of pins attracted by the magnet also increases but up to a certain limit. Later as the temperature decreases, the number of pins attracted by the magnet also decreases.

0

50

100

150

200

250

200 180 160 140 120 100 24

weight

attrac

ted (g)

Graph B/W temperature and weight attracted by the magnet

CONCLUSION

Magnetic materials should maintain a balance between temperature and magnetic domains (the atoms’ inclination to spin in a certain direction). When exposed to extreme temperatures, however, this balance is destabilized. Heat can result in the loss of magnetic properties. In other words, too much heat can completely ruin a magnet. Excessive heat causes atoms to move more rapidly, disturbing the magnetic domains. As the atoms are sped up, the percentage of magnetic domains spinning in the same direction decreases. This lack of cohesion weakens the magnetic force and eventually demagnetizes it entirely.

PRECAUTIONS

DO NOT TOUCH HOT MAGNET AND BOWL WITH NAKED HANDS. USE GLOVES.

WEIGHT THE PINS PRECISELY. DON’T USE PAPERCLIPS OTHER THAN THAT OF

IRON. DO NOT PREHEAT THE OVEN. DO NOT HEAT THE MAGNET FOR A LONG TIME.IT

MAY LOSE ITS MAGNETIC PROPERTY.

BIBLIOGRAPHY

NCERT Class XII Textbook www.sciencebuddies.com www.technopedia.com www.slideshare.com en.wikipedia.org Comprehensive Lab Manual