1. 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.

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.