JEE PYQ: Mathematics In Physics Question 23
Question 23 - 2019 (10 Jan Shift 1)
In the cube of side ‘$a$’ shown in the figure, the vector from the central point of the face ABOD to the central point of the face BEFO will be:
(1) $\frac{1}{2}a(\hat{k} - \hat{i})$
(2) $\frac{1}{2}a(\hat{i} - \hat{k})$
(3) $\frac{1}{2}a(\hat{j} - \hat{i})$
(4) $\frac{1}{2}a(\hat{j} - \hat{k})$
Show Answer
Answer: (3)
Solution
From figure, $\vec{r_1} = \frac{a}{2}\hat{i} + \frac{a}{2}\hat{k}$ $\vec{r_2} = \frac{a}{2}\hat{j} + \frac{a}{2}\hat{k}$ $\therefore \vec{r_2} - \vec{r_1} = \left(\frac{a}{2}\hat{j} + \frac{a}{2}\hat{k}\right) - \left(\frac{a}{2}\hat{i} + \frac{a}{2}\hat{k}\right) = \frac{a}{2}(\hat{j} - \hat{i})$
BETA
