The figure below shows two point charges q and q mowing rela

The figure below shows two point charges, q and -q mowing relative to an observer at point A. Point A is d/4 from the +q and 3d/4 from -q. find the magnetic field (both magnitude and direction) produced by the two charges at point A.

Solution

Magnetic field by a point charge is given by the equation B = (µ₀/4*)*(q*v*r/a²).

Magnetic field by +q at A = (µ₀/4*)*[16*q*v/d²]

Magnetic field by -q at A = (µ₀/4*)*[16*-q*v/9*d²]

Total Magnetic field at A = (µ₀/)*[32*q*v/9*d²].