Question

four identical charges q are placed at the corners of a square of side l how much work down

Answer 1

four identical charges ‘q’ are placed at the corner of a square of side length l.

then, work done by the configurations = potential energy of the configurations

if we assume ABCD is a square then,

potential energy of the configuration A and B = kq²/l

potential energy of the configuration B and C = kq²/ l

potential energy of the configuration C and D = kq²/l

potential energy of the configuration D and A = kq²/l

potential energy of the configuration A and C = kq²/(√2l)

potential energy of the configuration B and D = kq²/(√2l)

so, total potential energy = 4 × kq²/l + 2 × kq²/(√2l)

= 4kq²/l + √2kq²/l

= (4 + √2)kq²/l

hence, work done by the configurations= (4 + √2)kq²/l