If `veca,vecb,vecc,vecd` are unit vectors such that `veca.vecb=1/2`, `vecc.vecd=1/2` and angle between `veca xx vecb` and `vecc xx vecd` is `pi/6` then the value of `|[vecavecbvecd]vecc-[vecavecbvecc]vecd|=`

Options

A. `3//2`
B. `3//4`
C. `3//8`
D. 2

Answer

C

Explanation

`|[vecavecbvecd]vecc-[vecavecbvecc]vecd|`
`=(veca xx vecb) xx (vecc xx vecd)`
`=|veca xx vecb||vecc xx vecd|sin30^(@)`
`=sqrt(3)/2 xx sqrt(3)/2 xx 1/2=3/8`