Four circular loops of radii $1 \; CM$,$2 \; CM$,$3 \; CM$,and $4 \; CM$ carry the same electric current. At the center of which loop will the magnetic field be the strongest?

Name any three factors on which the magnitude of the magnetic field due to a solenoid depends.

How can you show that the magnetic field produced by a given electric current in a wire decreases as the distance from the wire increases?

$(a)$ Draw a schematic labelled diagram of a domestic wiring circuit which includes $(i)$ a main fuse,$(ii)$ a power meter,$(iii)$ one light point,and $(iv)$ a power plug.
$(b)$ Why is it necessary to connect an earth wire to electric appliances having metallic covers?

The diagram below shows two ways of connecting three bulbs $A, B$ and $C$ to a $220 \,V$ main in a room. Name the two arrangements. Which of them would you prefer for household electricity? Give two reasons.

The horizontal component of the Earth's magnetic field at a place is uniform and its direction is from south to north. $A$ high current flows through a horizontal power line at this place from west to east. Consider two points $A$ and $B$ at equal distances from the wire,respectively above and below it. Giving reasons,explain where the magnetic field is stronger: at $A$ or at $B$.