The component of a vector `r` along X-axis will have maximum value if

Options

A. r is along positive Y-axis
B. r is along positive X-axis
C. r makes an angle of `45^(@)` with the X-axis
D. r is along negative Y-axis

Answer

B

Explanation

Let r makes an angle `theta` with positive X-axis component of r along X-axis
`r_(x) = |r| cos theta`
`(r_(x))_("maximum") = |r| (cos theta)_("maximum")`
`=|r| cos 0^(@)= |r|` (`because cos theta` is maximum for `theta= 0^(@)`)
As `theta= 0^(@)`, r is along positive X–axis.