Two small balls having equal positive charge Q (coulumb) on each suspended by two insulating strings of equal length L (metre) from a hook fixed to a stand. The whole set-up is taken in a satellite into space where there is no gravity (state of weightlessness). Then tension (newtons) in each string is:

Explanation

Let A and B two charged balls suspended from hook, O as shown in figure.
(i) In the absesnce of gravity, tension in the strings is due to only coulomb's repulsive force. As such the two string will be in the same straight line making an angle of `180^(@)` with each other, the separation between the balls being 2L.
(ii) Tension in each string T=Coulomb's force between the charged balls. i,e.
`T=k_(e)(QxxQ)/((2L)^(2))=k_(e)(Q^(2))/(4L^(2))(N)`.