Magnetic field is produced by the flow of current in a straight wire. This phenomenon is based on-

Options

A. Faraday’s Law
B. Maxwell’s Law
C. Coulbom’s Law
D. Oersted’s Law

Answer

To determine the basis of the phenomenon where a magnetic field is produced by the flow of current in a straight wire, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Concept**: The first step is to recognize that a magnetic field is produced around a current-carrying conductor. This is a fundamental principle in electromagnetism.

2. **Historical Background**: The phenomenon was discovered by Hans Christian Ørsted in 1820. He found that an electric current flowing through a wire creates a magnetic field around it.

3. **Experimental Observation**: Ørsted conducted an experiment where he connected a wire to a DC battery. He placed a magnetic compass near the wire and observed that the compass needle deflected when the current flowed through the wire.

4. **Direction of Magnetic Field**: The direction of the magnetic field produced by the current can be determined using the right-hand rule. If you point the thumb of your right hand in the direction of the current, your fingers will curl in the direction of the magnetic field lines.

5. **Effect of Current Direction**: If the direction of the current is reversed, the direction of the magnetic field also reverses. This shows the direct relationship between the flow of current and the orientation of the magnetic field.

6. **Conclusion**: The phenomenon of a magnetic field being produced by a current-carrying wire is based on the principles of electromagnetism, specifically the interaction between electricity and magnetism as established by Ørsted's findings.

### Final Answer:
The phenomenon of a magnetic field being produced by the flow of current in a straight wire is based on the principles of electromagnetism, specifically discovered by Hans Christian Ørsted in 1820.

---