Physics

Problem

An electron of speed

2.0\times10^{7}\,\text{m s}^{-1}

enters perpendicularly into a uniform magnetic field of magnitude

0.010\,\text{T}

. Taking

m_e=9.1\times10^{-31}\,\text{kg}

and

e=1.6\times10^{-19}\,\text{C}

, the radius of the circular path described by the electron is closest to a)

0.57\,\text{cm}

1.1\,\text{cm}

0.11\,\text{cm}

11\,\text{cm}