A vector B is along positive y-axis and its vector product with another vector A is zero; then vector A could be

Step-by-step solution

Given that vector B is along the positive y-axis, we can write B = B j where B > 0 . The vector product of B and A is zero, which means B A = 0 . For the cross product of two non-zero vectors to be zero, the vectors must be parallel or anti-parallel to each other. This implies that A must also be directed along the y-axis. Therefore, A must be of the form A j . Among the given options, 5 j is the only vector along the y-axis. Answer: 5 j