A potential difference of 500 V is applied across a paralle plate capacitor. The separation between the plates is `2xx10^(-3)m`. The plates of the capacitor are vertical. An electron is projected vertically upwards between the plates with a velocity of `10^(5)m//a` and it moves undeflected between the plates. The magnetic field acting perpendicular to the electric field has magnitude of

Options

A. `0" " Wb//m^(2)`
B. `5//2" " Wb//m^(2)`
C. `10^(-6)" " Wb//m^(2)`
D. `10^(5)" " Wb//m^(2)`

Answer

B

Explanation

`evec(V)xxvec(B)=evec(B)" "impliesVB=E" "B-(E)/(V)`
Also 500 Volt `=E(2xx10^(-3)m)` .