Question

Given that both $P$ and $Q $ are greater than 1. The magnitude of $\overrightarrow{P} \, \times \,\overrightarrow{Q}$ cannot be

• A. equal to $PQ$
• B. less than $ PQ $
• C. more than $PQ$
• D. equal to $P/Q$.

Answer 1

Answer: (C)

$| \overrightarrow{P} \times \overrightarrow{Q} |$ = PQ sin $\theta$ and sin $\theta \, \leq$ 1
Also PQ sin $\theta$ can be equal to P/Q when sin $\theta = 1/Q^2$.
Thus (1), (2) and (4) are correct but (3) is not possible.