Who first observed that a current-carrying wire experiences a force when placed in a strong magnetic field?

Explain what is short circuiting and overloading in an electric supply.

Which is the direction of magnetic force acting on a current-carrying wire placed in a magnetic field?

How does the strength of the magnetic field at the centre of a circular coil of a wire depend on:
$(a)$ radius of the coil
$(b)$ number of turns in the coil.

$A$ student performs an experiment to study the magnetic effect of current around a current-carrying straight conductor. He reports that:
$(i)$ The direction of deflection of the north pole of a compass needle kept at a given point near the conductor remains unaffected even when the terminals of the battery sending current in the wire are interchanged.
$(ii)$ For a given battery,the degree of deflection of a $N$-pole decreases when the compass is kept at a point farther away from the conductor.
Which of the above observations of the student is incorrect and why?

Can a freely suspended current-carrying solenoid stay in any direction? Justify your answer. What will happen when the direction of current in the solenoid is reversed? Explain.