The angle which a vector `hat(i)-hat(j)+sqrt(2)hat(k)` makes with y-axis is

Options

A. `60^(@)`
B. `120^(@)`
C. `150^(@)`
D. `tan^(-1)(-(1)/(2))`

Answer

B

Explanation

`cosbeta=(A_(y))/(A)=(-1)/(sqrt((1)^(2)+(-1)^(2)+(sqrt(2))^(2)))=-(1)/(2)`
`therefore beta = 120^(@)`