Magnetic field due to a current-carrying solenoid is similar to the magnetic field of a:
Bar magnet
Horse-shoe magnet
Magnetic field due to a straight current-carrying conductor
None of the above
Hence, the correct option is A.
A solenoid that is carrying current has magnetic field lines similar to a:
From above fromula we can say, magnetic field due to a current carrying toroidal solenoid is independent of its radius.The magnetic field at the ends of a solenoid is