Question

The negative charge –q₂ is fixed while positive charge q₁ as well as the conducting sphere 'S' is free to move (figure). If the system is released from rest –

• A. Both S and q₁ move toward left
• B. q₁ move toward right while S moves left
• C. q₁ remain at rest, S moves to the left
• D. Both q₁ and S remain at rest

Answer 1

Answer: (B)

q₁ move toward right while S moves left

Answer 2

Let give small displacement to q.

The equilibrium will be stable if net force after giving displacement will be in direction of position of equilibrium.

F_e sin a ³ mg sin 2a. then net force will be directed toward vertex in initial equilibrium position

sin a ³ mg sin2 a

d-diameter of sphere and a is very small

× a ³ mg × 2 a

Q ³ = 9.8 × 10^–8 C