# Question

Two equal and opposite point charges form a dipole, as shown in Fig. 15.29.

(a) Add the electric fields due to each end at point P, thus graphically determining the direction of the field there.

(b) Derive a symbolic expression for the magnitude of the electric field at point P, in terms of k, q, d, and x.

(c) If point P is very far away, use the exact result to show that E ≈ kgd/x3.

(d) Why is it an inverse-cube falloff instead of inverse-square? Explain why it is not an inverse square falloff.

(a) Add the electric fields due to each end at point P, thus graphically determining the direction of the field there.

(b) Derive a symbolic expression for the magnitude of the electric field at point P, in terms of k, q, d, and x.

(c) If point P is very far away, use the exact result to show that E ≈ kgd/x3.

(d) Why is it an inverse-cube falloff instead of inverse-square? Explain why it is not an inverse square falloff.

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