In an experiment similar to Thomson's for determining the charge-to-mass ratio (e/m) of cathode rays, electrons travel at right angles through a magnetic field of strength $1.50 \times 10^{-4} \mathrm{~T}$. Given that they travel in an arc of radius 6 cm and that $\mathrm{e} / \mathrm{m}=1.76 \times 10^{11} \mathrm{Ckg}^{-1}$, calculate the speed of the electrons.