Appliances with higher power ratings are connected to which ampere line (in $A$)?

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

Describe in short an activity to:
$(i)$ demonstrate the pattern of magnetic field lines around a straight current-carrying conductor, and
$(ii)$ find the direction of the magnetic field produced for a given direction of current in the conductor. Name and state the rule to find the direction of the magnetic field associated with a current-carrying conductor. Apply this rule to determine the direction of the magnetic field inside and outside a current-carrying circular loop lying horizontally on a table. Assume that the current through the loop is anticlockwise.

If the direction of current is reversed,the direction of magnetic field is also reversed.

What is the frequency of $220 \ V$ $DC$ voltage? (In $Hz$)

What is the role of the two conducting stationary brushes in a simple electric motor?