If vectors are arranged as trigonal planar and have equal magnitude, it is an ideal case of zero resultant.
SinceECu2+/CuECu2+/Cuhas a greater positive value thanEH+/HEH+/H, the reaction that is feasible at the cathode is
Cu2+(aq)+2eCu(s)
The Wheatstone bridge is not suitable for measuring very low resistance because it is based on a ratio of two resistances, and the resolution of the bridge decreases as the ratio approaches 1. This means that the Wheatstone bridge is not accurate enough to measure very small changes in resistance.
This picture develops a clear understanding.
Yes, a vector which has zero magnitude is also a vector in case of two vectors travelling in opposite directions with equal magnitudes. At this case, the resultant vector has zero magnitude but it is still a vector. We call it a null vector.
