If A=3i+j+2k and B=2i-2j+4k then value of |A B | will be-

Correct answer: B. (b) A B=(ijk3122-24) =1 4-2 -2i-4 3-2 2j+(3 -2-1 2)k =8i-8j-8k ∴ Magnitude of A B=(A B) = 8^2+ (-8 )^2+ (-8 )^2=8 3

JEE · NEET Previous Year Question

$If A = 3 i + j + 2 k and B = 2 i - 2 j + 4 k then value of | A \times B | will be-$

Topic: NEET PYQ

Answer: B. Full step-by-step solution below.

Correct answer: B

(b) A \times B = (ij k 3122 - 24) = 1 \times 4 - 2 \times - 2 i - 4 \times 3 - 2 \times 2 j + (3 \times - 2 - 1 \times 2) k = 8 i - 8 j - 8 k ∴ Magnitude of A \times B = (A \times B) = 8^{2} + (- 8)^{2} + (- 8)^{2} = 83