What is short-circuiting in an electric supply?

How is the relative strength of a magnetic field shown around a magnet?

$(a)$ 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.

$A$ student performs an experiment to study the magnetic effect of current around a current-carrying straight conductor with the help of a magnetic compass.
He reports that:
$(i)$ the degree of deflection of the magnetic compass increases when the compass is moved away from the conductor.
$(ii)$ the degree of deflection of the magnetic compass increases when the current through the conductor is increased.
Which of the above observations of the student appears to be wrong and why?

$A$ device used for producing current is:

Describe the activity that shows that a current-carrying conductor experiences a force perpendicular to its length and the external magnetic field. How does Fleming's left-hand rule help us to find the direction of the force acting on the current-carrying conductor?