Name two types of wiring systems adopted for domestic wiring.

No two magnetic field lines can intersect each other. Explain.

Which of the following statements is incorrect for a current-carrying solenoid?

$(a)$ What are magnetic field lines? How is the direction of a magnetic field at a point determined?
$(b)$ Draw two field lines around a bar magnet along its length on its two sides and mark the field directions on them by arrow marks.
$(c)$ List any three properties of magnetic field lines.

The diagram below shows a coil connected to a centre zero galvanometer $G$. The galvanometer shows a deflection to the right when the $N$ pole of a powerful magnet is moved to the right as shown.
$(i)$ Explain why the deflection occurs in the galvanometer.
$(ii)$ Does the direction of current in the coil appear clockwise or anticlockwise when viewed from end $A$?
$(iii)$ State the observation in $G$ when the coil is moved away from $N$.
$(iv)$ State the observation in $G$ when,both coil and the magnet,are moved to the right at the same speed.

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