An electron of mass m and charge e moves in a circular path in a...

PHYSICS
WAEC 2020

An electron of mass m and charge e moves in a circular path in a magnetic field of flux density B. How long does it take to complete one orbit?

  • A. \(\frac{2me}{B\pi}\)
  • B. \(\frac{2B}{me\pi}\)
  • C. \(\frac{2\pi m}{Be}\)
  • D. \(\frac{Be}{2 \pi m}\)

Correct Answer: C. \(\frac{2\pi m}{Be}\)

Explanation

Motion of charged particles in Magnetic field

qvb = \(\frac{Mv^2}{r}\)

where q = e

Introducing Period (T) as time taken to complete one orbit = \(\frac{2πM}{qe}\)



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