2. DESIGN ENGINEERING – 2-a ELECTRONICS AND COMMUNICATION SUB ;- Electromagnetics  Sitapara Darshask (130640111028)  Thakkar Nirali (130640111029)  Patel Utkarsh (130640111022)  Shah Urmi (140643111003)  Patel Jay (130640111020) Guide By: Ms. parveen sheikh Head Of The Department: Mrs. Priti Jain Academic Year 2015-16

4.  We have seen that magnets can exert a force on objects without touching them. For this reason we speak of a magnetic field around a magnet, in the same way that we speak of an electric field around a charged object.

5.  A magnetic field is represented by drawing in "magnetic lines of flux".  These are lines drawn so that a tangent at any point will show the direction of the magnetic field.  The direction of a line of flux is from the North Pole to the South Pole, outside a magnet, from South to North inside the magnet.  (One line of flux may cause many lines of iron filings.)

6.  Weber - one magnetic line of flux is called a Weber (Wb) Wilhelm Eduard Weber

7.  Magnetic Flux - the entire group of lines of flux about a magnet, or in a region is called the magnetic flux.  Symbol is  - phi)

8.  An electric field exerts a straight attractive or repulsive force upon a charged object.  A magnetic field will exert a particular force upon a charged moving object.  This force is perpendicular to the motion of the charge. The force is proportional to the velocity of the moving charge.

9.  in terms of amount of force exerted per unit of moving charge - N/C  Use the idea that magnetic field strength is directly related to the concentration of flux lines. i.e. lines of flux per unit of area.

10. where B is measured in Tesla (T)  is measured in Webers (Wb) A is measured in square metres. (m 2 )

11.  e.g. In a 25m 2 area on the Earth, there are 1.25 x 10 -3 lines of flux measured. What is the field strength of the Earth's magnetic field? *note this is a constant value