If the key in the arrangement (Figure) is taken out (the circuit is made open) and magnetic field lines are drawn over the horizontal plane $ABCD$,the lines are

The laws of electromagnetism tell us that energy can be transferred from one object to another:

$(a)$ What is the function of an earth wire in electrical instruments? Why is it necessary to earth the metallic electric appliances?
$(b)$ Explain what is short-circuiting and overloading in an electric supply.
$(c)$ What is the usual capacity of the fuse wire in the line to feed:
$(i)$ lights and fans?
$(ii)$ appliances of $2 \,kW$ or more power?

It is established that an electric current through a metallic conductor produces a magnetic field around it. Is there a similar magnetic field produced around a thin beam of moving $(i)$ alpha particles,$(ii)$ neutrons? Justify your answer.

Differentiate between overloading and short-circuiting.

The magnetic field produced by a current flowing through a straight conductor is inversely proportional to the $........$.