Question
The number of vectors of unit length perpendicular to the vectors $\hat{a} = \hat{i} + \hat{j}$ and $\vec{b} = \hat{j} + \hat{k}$ is
The number of vectors of unit length perpendicular to the vectors $\hat{a} = \hat{i} + \hat{j}$ and $\vec{b} = \hat{j} + \hat{k}$ is