The most important safety method used for protecting home appliances from short circuiting or overloading is

How is the strength of the magnetic field at a point near a wire related to the strength of the electric current flowing in the wire?

Which instrument converts mechanical energy to electrical energy?

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.

$A$ uniform magnetic field is directed vertically upwards. In which direction should an $\alpha$-particle (which is a positively charged particle) be projected in this field so that it is deflected southwards? Name and state the rule used to find the direction in this case.

If you strike a sharp edge of a metallic knife against the north pole of a bar magnet,it will induce a north pole.