Question

$If \vec{a} and \vec{b} are mutually perpendicular then \vec{a} \cdot \vec{b} =$

Answer: 0

Solution :-

We know that if $\vec{a} and \vec{b}$ are mutually perpendicular then angle $θ$ between $\vec{a} and \vec{b}$ are $\frac{π}{2}$ .
Hence, $θ = \frac{π}{2}$

\begin{aligned} also we know that \\ \vec{a} \cdot \vec{b} & = & ∣ \vec{a} ∣ \cdot ∣ \vec{b} ∣ \cdot cos θ \\ ∴ \vec{a} \cdot \vec{b} & = & ∣ \vec{a} ∣ \cdot ∣ \vec{b} ∣ \cdot cos \frac{π}{2} (∵ θ = \frac{π}{2}) \\ = & ∣ \vec{a} ∣ \cdot ∣ \vec{b} ∣ \cdot 0 \\ = & 0 \cdot \end{aligned}

Hence, If $\vec{a} and \vec{b}$ are mutually perpendicular then $\vec{a} \cdot \vec{b} = 0 \cdot$

So, correct answer is option-2, $\to 0$

#Vector Algebra #BSEB PYQ 2017 #Mathematics #BSEB PYQs

Question

Ifa⃗andb⃗are mutually perpendicular thena⃗⋅b⃗=

Solution :-

$If \vec{a} and \vec{b} are mutually perpendicular then \vec{a} \cdot \vec{b} =$