Question

An electric charge in uniform motion produces:

• A. only electric field
• B. only magnetic field
• C. Both electric and magnetic field
• D. Neither electric nor magnetic field

Hint:

Moving charge \(\Rightarrow\) always produces magnetic field.

Answer 1

The Correct Option is C

To understand the phenomena associated with an electric charge in uniform motion, we need to consider electromagnetic theory, primarily derived from Maxwell's equations.

Conceptual Understanding:

• Electric Field: A charge at rest produces an electric field around it that exerts a force on any other charges present in the field.
• Magnetic Field: When an electric charge moves, it creates a magnetic field in addition to the electric field.

Explanation:

According to electromagnetic theory, a moving charge generates both electric and magnetic fields:

1. When a charge is at rest, it only produces an electric field.
2. Upon setting the charge in motion with a constant velocity (uniform motion), it creates a magnetic field as well. This is because, in the context of electromagnetism, a moving charge is equivalent to an electric current, which is known to produce a magnetic field according to Ampère's circuital law.

Why "Both electric and magnetic field" is the correct answer:

In the question, when it mentions an "electric charge in uniform motion," it refers to charged particles moving through space. This motion means there is a transformation from just electric field production (at rest) to both electric and magnetic fields (in motion). Therefore, the correct option is:

• Both electric and magnetic field

Conclusion:

In summary, a uniformly moving electric charge produces both electric and magnetic fields. The presence of motion is the key differentiator that adds the magnetic component to the existing electric component.