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

All the distribution circuits for domestic purposes are parallel connections.

Which instrument is used to know the presence of an electric current in a circuit?

Name the rule used to find the direction of force on a current-carrying conductor placed in a magnetic field.

In a region where magnetic field lines are close to each other,what is the nature of the magnetic field?

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?