Question

Why does a magnetic compass needle pointing North and South in the absence of a nearby magnet get deflected when a bar magnet or a current-carrying loop is brought near it. Describe some salient features of magnetic lines of field concept.

Answer 1

• Current carrying loops acts as bar magnets which have associated lines of field. 
• This changes existing earth’s magnetic field and a deflection results. Magnetic field has both direction and magnitude. 
• Magnetic field lines emerge from north pole and enter south pole. 
• The magnetic field strength is represented diagrammatically by the degree of closeness of the field lines. 
• Two values of net field cannot exist as a single point as field lines cannot cross each other. 
• Only one value, a unique net value, can exist. 
• If in a given region, lines of field are shown to be parallel and equispaced, the field is understood to be uniform.