Also we know that current density \(j = \frac{i}{A}\)

Hence \(j\) is different for different area of cross-sections. When \(j\) is different, then \(E\) is also different. Thus \(E\) is not constant. The drift velocity \({v_d}\) is given by \({v_d} = \frac{j}{{ne}}=\) different for different \(j\) values. Hence only current i will be constant.