KCET2017PhysicsCurrent Electricity
If ( A =2 i +3 j +8 k ) is perpendicular to ( B =4 j -4 i + k ), then the value of ' ( ) ' is
Options
- A( 1 2 )
- B(- 1 2 )
- C( 11 )
- D( -1 )
Correct answer
A. ( 1 2 )
Step-by-step solution
Given, A =2 i +3 j +8 k and B =4 j -4 i + k Now, A B =|A||B| Given, the two vectors are perpendicular. Therefore =90^ A B = .|A| |_ B 90^ A B =0 (2 i+3 j+8 k) (4 j-4 i+ k)=0 8-12+8 =0 -4+8 =0 = 1 2