MAGNETISM biomedical physics final.pptx

biomedical physics

1. MAGNETISM BY: HOPE PETER SHRUTI

2. DEFINITION A magnet is an object that produces a magnetic field which has properties of power attraction and repulsion for certain materials and tendency when free to rotate to come to rest position in North South direction only

3. EXAMPLES OF MAGENETISM Examples of magnetic substances include iron, nickel, cobalt, stainless steel, and many rare earth metals. Diamagnetic materials like copper and gold are weakly repelled by a magnetic field. Paramagnetic materials like calcium and aluminium are weakly attracted by a magnetic field

4. TYPES OF MAGNET Natural magnets: known as iodestones which is a type of iron ore with magnetic properties Artificial magnets: materials in which magnetic properties are produced artificially such as iron, nickel Temporal magnets: that lose their magnetic property easily and quickly eg soft iron Permanent magnets: which retain their properties more longer and difficult to magnetise eg steel Electromagnet: an electric current produces magnetic effects and a coil of wire carrying a current act as an electromagnet

5. MAGNETIC FIELD Magnetic Field is the region around a magnetic material or a moving electric charge within which the force of magnetism act. Magnetic field around a magnet can be detected by using a magnetic compass. Travel away from north pole towards south pole Magnetic field lines are close continuous curves No two lines intersect each other Tend to repel each other helps distribution of magnetic field

6. GEOMETRIC LENGTH AND MAGNETIC LENGTH Actual length of bar magnet AB is defined as geometric length Magnetic lines occurs 6/7 of geometric length

7. EQUATORIAL LINE The line passing through the center of magnet and perpendicular to long axis of magnet

8. MAGNETIC MERIDIAN A vertical line passing perpendicular to long axis of magnet.

9. FERROMAGNETISM The phenomenon exhibited by material like eg iron that become magnetized in magnetic field and retain their magnetism even after removal of magnetic field DIAMAGNETISM The phenomenon exhibited by material like copper that become magnetized in a magnetic field with polarity opposite to the magnetic force

10. CATERGORY NATURAL MAGNETS ARTIFICIAL MAGNETS Magnetic strength Have lower magnetic strength High magnetic strength and powerful magnetic field magnetisation Magnetisation occurs naturally Requires magnetizing process through exposure to a magnetic field permanence Retain magnetism indefinity Can be demagnetised and remagnetised through manipulation Shape and size Have irregular shapes and limited customization Have a wide range of shapes and sizes and highly customized

11. This Photo by Unknown Author is licensed under CC BY-NC This Photo by Unknown Author is licensed under CC BY-NC-ND

12. PROPERTIES OF MAGNET Setting in north-south direction Behaviour of like and unlike poles Magneti field Attraction of objects of magnetisable material Transmission of properties

13. ELECTROMAGNET Consist of coil of wire wound on a soft iron bar When current passthrough the coil, magnetic field set up and soft iron core is magnetized by induction, so that its field id added to that produced by current A strong magnetic field is produced, which can turn on and off as required by starting or stopping current Soft iron is often chosen for core because it can be easily magnetized and demagnetized

14. MOLECULAR THEORY OF MAGNETISM If we break a magnet into two parts, each part becomes a complete magnet Individual molecule of the magnet act as a tiny molecular magnet Their magnetic properties may be due to electrons rotation in their orbits, which constitute minute electric current and thus produce magnetic properties When material is magnetized, the molecular magnets are arranged in an order so that their properties augmented and become apparent

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