Question

If the scalar product of two vectors is negative, then the angle between them has the range

• A. $0\le \theta <{90}^{\circ }$
• B. $\theta ={90}^{\circ }$
• C. ${90}^{\circ }<\theta \le {180}^{\circ }$
• D. None of these

Answer 1

The correct option is C ${90}^{\circ }<\theta \le {180}^{\circ }$

Scalar product is negative for ${90}^{\circ }<\theta \le {180}^{\circ }$, as in this range, $\cos \theta$ is negative