The correct answer is option 1: The magnetic field produced by a current-carrying straight wire at a point outside the wire depends inversely on the distance from it.
To understand this, let`s consider the equation that describes the magnetic field produced by a current-carrying wire, known as the Biot-Savart law. According to this law, the magnetic field at a point depends on the current in the wire and the distance from the wire.
In the case of a straight wire, the magnetic field lines form concentric circles around the wire. The strength of the magnetic field decreases as we move away from the wire. This means that as the distance from the wire increases, the magnetic field gets weaker.
The relationship between the magnetic field and distance is inversely proportional. This means that as the distance doubles, the magnetic field strength decreases by a factor of two. Mathematically, we can express this relationship as B ∝ 1/r, where B is the magnetic field strength and r is the distance from the wire.
Therefore, the correct answer is that the magnetic field produced by a current-carrying straight wire at a point outside the wire depends inversely on the distance from it.