Question

Draw a graph of E versus r for r >> a.

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Answer 1

Answer

Net field at P is given by

EP=EB−EA=4πϵ01((r−a)2q−(r+a)2q)=4πϵ0q(r2−a2)24ar=4πϵ01(r2−a2)22pr along BP .

for r>>a

EP=4πϵ01r32p

solution