The magnetic field produced by a current carrying conductor decreases as the ____________ increases.

Correct option is C

​The correct answer is (c) distance.

• The magnetic field produced by a current-carrying conductor decreases as the distance from the conductor increases.

• According to Ampère's Circuital Law and the Biot-Savart Law, the magnetic field around a straight current-carrying conductor is inversely proportional to the distance from the conductor. Mathematically, the magnetic field strength (B) at a distance (r) from a long straight conductor carrying current (I) is given by:

                                                                            $$B = \dfrac{\mu_0 I}{2\pi r}$$​        

  where:

  • B = Magnetic field
  • I = Current
  • r = Distance from the conductor
  • μ₀ = Permeability of free space

  As r (distance) increases, B (magnetic field strength) decreases.

Information Booster:

Magnetic Field and Current:

• The magnetic field produced by a current-carrying conductor forms concentric circles around the conductor. The field is strongest near the conductor and decreases with distance.
• Right-Hand Thumb Rule: When the right hand is curled around the conductor, with the thumb pointing in the direction of the current, the fingers show the direction of the magnetic field.

Key Concepts:

• Biot-Savart Law: Describes the magnetic field generated by an electric current.
• Ampère’s Law: Relates the magnetic field around a closed loop to the total current passing through the loop.