Question

Why isn't force between 2 equal charges at midpoint of the distance between them is not equal to zero?

Answer 1

How do you know it is not 0 ?

Answer 2

are you talking abotu dipoles?? 2 equal charges but opposite in nature?? if yes then you are right and i would love to explain!

Answer 3

The answer at the back of the book was not zero.

Yes , it is a dipole.

Answer 4

well then
consider point p.. can you tell me at point p.. what is the direction of the electric field due to charge +q?

Answer 5

electric field is away from +q and towards -q.

Answer 6

wait wait.. just tell me direction of field due to +q at point p..!!

Answer 7

away ( or opposite) from +q i.e. in the figure towards right at p

Answer 8

ok..
use left and right notation only

now tell due to -q .. where will it be?

Answer 9

towards right

Answer 10

exactly.. so you see.. the two fields add up in between.. and hence you can't have null point ( E=0)

Answer 11

oh now i got it. so electric field must be double at this point p? sorry it might be a stupid question but i have to get few confusions cleared

Answer 12

need not be double.. the two fields just add up... but they need not have the same value.. for our example p is closer to -q .. hence the field due to -q is stronger than +q

but if you are talking about mid point specifically then you are SPOT ON right.. field will get doubled ;-)

Answer 13

Thank u for the explanation