An the electron undeflected when passing perpen to mutually perpendicular electric and magnetic fields magnetic field is 8 Gauss and the electric field `Vm^(-1)`the velocity of the electron is

Options

A. `2xx10^(6)ms^(-1)`
B. `5xx10^(5)ms^-(1)`
C. `6xx10^(6)ms^(-1)`
D. `6xx10^(5)ms^(-1)`

Answer

B

Explanation

Magnetic field ,B =8 Gauss
Electric field ,`E=400Vm^(-1)`
The expression for the velocity of the electron is given as
`V=(E)/(B)`
`implies V=(400)/(8xx10^(-4)``(because8 Gauses =8xx10^(-4)Wbm^(-2))`
`=50xx10^(4)`
`therefore V=5xx10^(5)ms^(-1)`