Question

Let `vecr, veca, vecb` and `vecc` be four non-zero vectors such that `vecr.veca=0, |vecrxxvecb|=|vecr||vecb|,|vecrxxvecc|=|vecr||vecc|` then
`[(veca, vecb, vecc)]=`
A. `-1`
B. `0`
C. `1`
D. `2`

Answer 1

Correct Answer - B
We have
`{:(vecr.veca=0impliesvecr_|_veca),(|vecrxxvecb|=|vecr||vecb|impliesvecr_|_vecb),("and"|vecrxxvecr|=|vecr||vecc|impliesvecr_|_vecc):}}impliesveca, vecb vecc` are coplanar.
Hence `[(veca, vecb, vecc)]=0`