Three identical small balls

PHYSICS · Subjective · CBSE · Physics · Electric Charges and Fields · Electric Charges and Fields

Problem

Three identical small balls, each of mass

0.1\,\text{g}

, are suspended from one point by silk threads of length

l=20\,\text{cm}

. What charge should be imparted to each ball for each thread to form an angle of

\alpha=30^\circ

with the vertical?