Which of the following is used in a fire alarm?

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.

Draw a labelled circuit diagram of a simple electric motor and explain its working. In what way are these simple electric motors different from commercial motors?

State the energy change which takes place when a magnet is moved inside a coil having a galvanometer at its ends. Name this phenomenon.

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

$A$ current through a horizontal power line flows in east to west direction. What is the direction of magnetic field at a point directly below it and a point directly above it?