A charged particle is moving on a circular path with velocity v in a uniform magnetic field B. If the velocity of the charged particle is doubled and the strength of the magnetic field is halved, then the radius becomes _.
Correct answer: C. 4 times
- A. 8 times
- B. 2 times
- C. 4 times
- D. 16 times
Explanation
Magnetic Force = Centripetal Force. qvB = mv²/r so qB = mv/r. Therefore r can be written as r = mv/qB. Now, if v is doubled, r will double. If B is halved, r will double. So overall, r will become 4 times. Hence Option C is correct.
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About Electromagnetism
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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