Question:
Mark $(\sqrt{)}$ against the correct answer in each of the following:
If $\vec{a}=(\hat{i}-2 \hat{j}+3 \hat{k})$ and $\overrightarrow{\mathrm{b}}=(\hat{\mathrm{i}}-3 \hat{\mathrm{k}})$ then $|\overrightarrow{\mathrm{b}} \times 2 \overrightarrow{\mathrm{a}}|=?$
A. $10 \sqrt{3}$
B. $5 \sqrt{17}$
c. $4 \sqrt{19}$
D. $2 \sqrt{23}$
Solution: