If a point $\bar r$ lies on the line joining position vectors $\bar a$ and $\bar b$, then in the representation $\bar r=\bar a+\lambda(\bar b-\bar a)$, the vector $\bar r-\bar a$ is
Aperpendicular to $\bar b-\bar a$
Bparallel to $\bar b-\bar a$
Cequal to $\bar a+\bar b$
Da unit vector for all $\lambda$
Answer & Solution
Correct answer: B. parallel to $\bar b-\bar a$
From $\bar r=\bar a+\lambda(\bar b-\bar a)$, we get $\bar r-\bar a=\lambda(\bar b-\bar a)$. Since one vector is a scalar multiple of the other, they are parallel.
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