In a chamber a uniform magnetic field of $6.5\;G(1G= 10^{-4})$ is maintained . An electron is short into the field with a speed of $4.8 \times 10^{6} m/s$ normal to the field , explain why the path of the electron is a circle Determine the radius of the circular orbit. $(e=1.6 \times 10^{-19} \;C,m_e= 9.1 \times 10^{-31} \;kg)$

Question

$\begin{array}{1 1} 42\;cm \\ 4.2\;cm \\ 42\;m \\ 4.2\;m \end{array}$