A solid metallic cylinder carriers a direct current. The magnetic field produce by it exists

If a long hollow copper pipe carriers a direct current, the magnetic field associated with the current will be:

If a long hollow copper pipe carriers a direct current, the magnetic field associated with the current will be:

If a long hollow copper pipe carriers a direct current, the magnetic field associated with the current will be:

If a long hollow copper pipe carriers a direct current, the magnetic field associated with the current will be:

The direction of the magnetic field produced by a linear current is given by

If a copper rod carries a direct current, the magnetic field associated with the current will be_________

If a long copper rod carries a direct current, the magnetic field associated with the current will be