The magnitude of an $AC$ voltage used in other countries like America $(USA)$ is $.........$ and its frequency is $.......$.

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

$A$ uniform magnetic field exists in the plane of paper pointing from left to right as shown in Figure. In the field,an electron and a proton move as shown. The electron and the proton experience:

How will the magnetic field produced in a current-carrying circular coil change if we increase the:
$(i)$ value of current flowing through it?
$(ii)$ distance of point $P$ from the coil?
$(iii)$ number of turns of the coil?

The magnetic field produced by a current flowing through a straight conductor is inversely proportional to the $........$.

Who first observed the magnetic effect of an electric current?