What is the nature of the magnetic field lines passing through the center of a current-carrying circular loop?

Who proposed the principle of electromagnetic induction?

Mention the shape of the magnetic field lines around a current-carrying straight conductor.

$A$ uniform magnetic field is directed vertically upwards. In which direction should an $\alpha$-particle (which is a positively charged particle) be projected in this field so that it is deflected southwards? Name and state the rule used to find the direction in this case.

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

$A$ coil of insulated wire is connected to a galvanometer. Explain what happens if a bar magnet with its north pole towards one face of the coil is:
$(i)$ moved quickly towards the coil,
$(ii)$ kept stationary inside the coil,and
$(iii)$ moved quickly away from the coil?