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 , 10 Years ago
Grade 11
2 Answers
Aditi Chauhan
Last Activity: 10 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