This question involves the concept of the scalar product.
The magnitude of the scalar product will be "0".
The scalar product, also known as the dot product of the two vectors is given by the following formula:
[tex]A.B = |A||B|Cos\theta[/tex]
where,
Therefore,
[tex]A.B = (1)(1)Cos90^o = (1)(1)(0)[/tex]
A.B = 0
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