The strength of the magnetic field at a point r near a long straight current carrying wire is B. The field at a distance r/2 will be:
Correct answer: C. 2B
- A. B/2
- B. B/4
- C. 2B
- D. 4B
Explanation
The magnetic field (B) produced by a long, straight current-carrying wire is inversely proportional to the distance (r) from the wire. Therefore, if the distance is halved (to r/2), the magnetic field strength will double (to 2B).
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Magnetic flux density and magnetic flux describe the strength of a magnetic field and the field passing through a surface. A charged particle moving through a magnetic field experiences a force perpendicular to its velocity and may follow circular or helical motion, depending on the angle between velocity and field.
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