A horizontal circular groove is made in a wooden board. Two positive charges (q each) are placed in the groove at a separation of 90∘ (see figure). Where shall we place (in the groove) a third charge and what shall be its magnitude such that all three of them remain at rest after they are released. Answer for two cases:
Neglect friction and assume that the groove is very thin just wide enough to accommodate the particles.
Take: sin22.5∘=0.38 ; cos22.5∘=0.92.
