Question:
Mark $(\sqrt{)}$ against the correct answer in each of the following:
If a vector makes angle $a, \beta$ and $y$ with the $x$-axis, $y$-axis and $z$-axis respectively then the value of $\left(\sin ^{2} a+\sin ^{2} \beta+\sin ^{2} y\right)$ is
A. 1
B. 2
C. 0
D. 3
Solution:
