63. Two small charged balls in a vacuum, whose charges q1 = q2 = 40 nC with a mass m = 8.0 mg each are suspended at one point on light silk threads of the same length. If the balls are dispersed so that the angle between the strands is α = 90 °, then the length of each strand l is ... cm.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)