Two identical pith balls, each carrying a charge q, are suspended from a common point by two strings of equal length l, Find the mass of each ball if the angle between the strings is 2θ in equilibrium.
Simran Bhatia
12 Years agoGrade 11
2 Answers
Aditi Chauhan
12 Years ago
Sol. Electric force = kq^2/(ℓ sin Q + ℓ sin Q)^2 = kq^2/4 ℓ^2 sin^2
So, T Cos θ = ms (For equilibrium) T sin θ = Ef
Ef tan θ = Ef/mf
⇒ mg = Ef cot θ = kq^2/4ℓ^2 sin^2θ cot θ = q^2 cot θ/ℓ^2 sin^2θ 16πE base 0
Or m = q^2 cotθ/16πE base 0ℓ^2 Sin^2θg