If `vecA=2hati+4hatj` and `vecB=6hati+8hatj` and A and B are the magnitudes of `vecA` and `vecB`, then which of the following is not true?

Options

A. `vecAxxvecB=vec0`
B. `(A)/(B)=(1)/(2)`
C. `vecA,vecB=48`
D. `A=5`

Answer

C

Explanation

`vecA=3hati+4hatj,vecB=6haii8hatj`
`vecAxxvecB=|{:(hati,hatj,hatk),(3,4,0),(6,8,0):}|=0hati+0hatj+0hatk=vec0`
`A=sqrt(3^(2)+4^(2))=5 & B=sqrt(6^(2)+8^(2))=10`
`vecA.vecB=(3hati+4hatj).(6hatij+8hatj)=18+32=50`