Question

A current carrying wire in the neighbourhood produces _________
A) No field
B) Electric field only
C) Magnetic field only
D) Electric and magnetic fields

Answer 1

Hint: The answer of the question can be given by knowing the Oersted’s Experiment of the action of current on magnets. Note that, outside of the conductor there should be no electric field due to electrons. Because, the conductor is not charged.

Complete answer:
Scientist Oersted observed that if current is flowing through a wire a magnetic field is created outside wire. When the current flow is stopped the magnetic field vanishes. And for the increase in the current the magnetic field intensity is also increased. Here, the wire acts as a magnet. So it creates magnetic lines of force. Hence the magnetic field is flowing in the direction perpendicular to the direction of current.
Therefore the current produces the magnetic field. Hence the correct option is C.
An electric field produced by the charge exists in the conductor.
if a positive charge is put in any medium then there would be electric field lines in that medium starting from +ve charge to -ve charge.
Currently carrying wire doesn’t produce an electric field because wire is basically neutral because of the existence of the same amount of protons as electrons. So, outside of the conductor there should be no electric field as the conductor is not charged.

Hence, A current carrying wire in the neighbourhood produces Magnetic fields only. So, option (C) is correct.

Additional information:
Potential difference between two points is defined as the total amount of work done in moving the positive charge from one point to another. The electric field is also due to the charge present on the particular area. It is measured in volt per metre. And it can also be said as the electric force.

Note: In Oersted's experiment the deflection of a magnetic needle is shown due the current flow. There are some observation about the deflection:
If the current flow is stopped there is no more deflection that can be shown in the magnetic needle that mens the needle comes back to its initial position.
The deflection is increased due to increase in the current flow.
The direction of the deflection becomes opposite when the direction of the current becomes opposite.
There is no deflection in the magnetic needle if the current is flowing through the wire by keeping the wire perpendicular to the needle.