Answer Happy

4 A particle with charge q is stationary near the origin. It is given a time-dependent acceleration in the z direction, as illustrated in the image below. Time A very large distance along the x axis the resulting electric field is in the z direction and has the form -q [a] E₂(x, t): 4π€0x²¹ where the square brackets indicate the acceleration of the charge is to be evaluated at the retarded time, t -x/c. State why the retarded time must be used and sketch the variation of the field with x at some fixed time after the charge has stopped accelerating. [5] Acceleration =