An electron moving with a velocity vec$(v)=5\mathrm{.}0{10}^7\frac{m}{s}$hat$(i)$ enters a region of space where perpendicular electric and a magnetic fields are present. The electric field is vec$(E)={10}^4\frac{V}{m}$hat$(j).$ What magnetic field will allow the electron to go through the region without being deflected?

vec$(B)=+2\mathrm{.}0{10}^{-4}$That$(k)$

vec$(B)=-2\mathrm{.}0{10}^{-4}$That$(j)$

vec$(B)=+2\mathrm{.}0{10}^{-4}$That$(j)$

vec$(B)=+5\mathrm{.}0{10}^{-4}$That$(k)$

vec$(B)=-2\mathrm{.}0{10}^{-4}$That$(k)$