$\overrightarrow{\mathrm{P}} ও \overrightarrow{\mathrm{Q}}$ দুটি ভেক্টর রাশি। $\overrightarrow{\mathrm{P}} ও \overrightarrow{\mathrm{Q}}$ পরস্পর লম্ব হবে যখন—

$\overrightarrow{\mathrm{p}}=0$

$\vec{Q}=0$

$\overrightarrow{\mathrm{P}} . \overrightarrow{\mathrm{Q}}=0$

$\overrightarrow{\mathrm{P}} \times \overrightarrow{\mathrm{Q}}=0$