List two methods of producing magnetic fields.

The figure shows a long solenoid,a cylindrical coil of a number of turns of insulated copper wire,connected to a battery through an ammeter $A$ and a rheostat $Rh$.
$(i)$ Which end of the solenoid is a $N$-pole and which end is a $S$-pole?
$(ii)$ Draw the magnetic field lines inside the solenoid and indicate their directions. Are magnetic field lines closed?
$(iii)$ How can you increase the strength of the magnetic field inside the solenoid? Give two methods.

If field lines of a magnetic field are crossed at a point,what does it indicate?

Why does a compass needle get deflected when brought near a bar magnet?

Who proposed the principle of electromagnetic induction?

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.