Hello My name is Udit Gupta I am here to give you a brief introduction in Mac You can find me at: https://unacademy.com/user/udit 13 netism
Introduction If a charge q is placed at rest at a point F near a metallic wire carrying a current i, it experiences almost no force. We conclude that there is no appreciable electric field at the point P. This is expected because in any volume of wire (which contains several thousand atoms) there are equal amounts of positive and negative charges. The wire is electrically neutral and does not produce an electric field. Rest
Introduction In fact, there is a small charge density on the surface of the wire which does not produce an electric field near the wire. This field is very small and we shall neglect it. However, if the charge q is projected from the point P in the direction of the current (refer figure), it is deflected towards the wire (q assumed positive). 7
Introduction There must be a field at P which exerts a force on the charge when it is projected, but not when it is kept at rest. This field is different from the electric field which always exerts a force on a charged particle whether it is at rest or in motion. This new field is called magnetic field and is denoted by the symbol B .The force exerted by a magnetic field is called magnetic force.
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If a charged particle is projected in a magnetic field, in general, it experiences a magnetic force. By projecting the particle in different speeds, we can observe the following facts about the magnetic force. (a) There is one line through the point P, such that, if the velocity of the particle is along this line, there is no magnetic force. We define the direction of the magnetic field to be along this line (the direction is not uniquely detined yet, because there are two opposite directions along any line)
(b) If the speed of the particle is v and it makes an angle 0 with the line identified in (a), i.e., with the direction of the magnetic field, the magnitude of the magnetic force is proportional to lusin (c) The direction of the magnetic force is perpendicular to the direction of the magnetic field as well as to the direction of the velocity (d) The force is proportional to the magnitude of the charge q and its direction is opposite for positive and negative charges. All the above facts maybe explained if we define the magnetic field by the equation e|
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A Mechanical Engineer from NIT Allahabad here to help learners with physics. Also a Star ⭐ educator.