A mono energetic electron beam with electron speed of $5.20 \times 10^6 ms^{-1}$ is subjected to a mognetic field of $1.30 \times 10^{-4}\;T$ , normal to the beam velocity .What is the radius of the circle traced by the beam , given $\large\frac{e}{m}$ for electron equals $1.76 \times 10^{11} ckg^{-1}$
