Two pith balls carrying equal charges are suspended from a common point by strings of equal length; the equilibrium separation between them is r. Now the strings are rigidly clamped at half the height. The equilibrium separation between the balls now becomes

Question

Dr. Abubacker · Accepted Answer

[Solution from source] For a ball at equilibrium, tan θ = F/mg; with small angles tan θ ≈ (r/2)/L, so (r/2)/L = kq²/(r²mg), giving r³ ∝ L. Clamping at half the height halves the effective length, so r′³ = r³/2 and r′ = r/∛2. Answer (2).

Q. Two pith balls carrying equal charges are suspended from a common point by strings of equal length; the equilibrium separation between them is r. Now the strings are rigidly clamped at half the height. The equilibrium separation between the balls now becomes

Explanation

Reviewed by Dr. Abubacker

Want to attempt the full paper?