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 is C

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 = \(\frac{2πM}{qe}\)