At the centre of which of the following four circular rings has the maximum magnetic field while passing equal current through each of them?

With the help of a labelled circuit diagram,illustrate the pattern of field lines of the magnetic field around a current-carrying straight long conducting wire. How is the Right-Hand Thumb Rule useful to find the direction of the magnetic field associated with a current-carrying conductor?

Which type of magnet is used in a crane to lift cars?

$A$ coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is held stationary inside the coil?

If a circular loop is made of $6$ closely wound turns instead of a single turn,the magnetic field produced at the center of the loop becomes $.........$ times stronger.

Draw the pattern of magnetic field lines through and around a current-carrying circular loop of wire. How would the strength of the magnetic field produced at the centre of the circular loop be affected if: $(i)$ the strength of the current passing through this loop is doubled? $(ii)$ the radius of the loop is reduced to half of the original radius?