In the electric field shown in figure, the electric field lines on the left have twice the separation as that between those on the right. If the magnitudes of the fields at point `A` is `40NC^(-1)`, calculate the force experienced by a proton placed at point `A`. Also find the magnitude of electric field at point `B`

Options

A. `15NC^(-1)`
B. `20 NC^(-1)`
C. `25 NC^(-1)`
D. `30 NC^(-1)`

Answer

b

Explanation

Force on proton at point `A`
`F= qE_(A)= 1.6xx10^(-19)xx40= 6.4xx10^(-18)N`
Since separation between electric field lines at point `B` is twice as that at the point `A`, electric field at point `B`,
`E_(B)= 40xx1/2= 20NC^(-1)`