The number of vectors of unit length perpendicular to the vectors $\mathbf{a} = 2\hat{i} + \hat{j} + 2\hat{k}$ and $\mathbf{b} = \hat{j} + \hat{k}$ is

two

The correct answer is Option (2) → two ##

The number of vectors of unit length perpendicular to the vectors $\mathbf{a}$ and $\mathbf{b}$ is $\mathbf{c}$ (say)

i.e., $\mathbf{c} = \pm (\hat{\mathbf{a}} \times \hat{\mathbf{b}})$.

So, there will be two vectors of unit length perpendicular to the vectors $\mathbf{a}$ and $\mathbf{b}$.