Three charges are placed at the three vertices of an equilateral triangle of side a as shown in the figure. The force experienced by the charge placed at the vertex A in a direction normal to B C is

Step-by-step solution

Resultant force F ' = F 2 + F 2 + 2 F F cos 120 ° = F ∵ cos 120 ° = - 1 2 Now, from figure F = F ' 2 + F ' ' 2 + 2 F ' F ' ' cos 90 ° Now, the force normal to B C at vertex A is F ' ' = F 2 - F ' 2 = 0 ∵ F ' = F