- Home
- Standard 11
- Physics
3-1.Vectors
medium
જો સદિશ $ 2\hat i + 3\hat j + 8\hat k $ એ સદિશ $ 4\hat j - 4\hat i + \alpha \hat k $ ને લંબ હોય, તો $ \alpha$ નું કેટલું હશે?
A
$-1$
B
$0.5$
C
$-0.5$
D
$1$
(AIPMT-2005)
Solution
(c) Given vectors can be rewritten as $\overrightarrow A = 2\hat i + 3\hat j + 8\hat k$ and $\overrightarrow B = – 4\hat i + 4\hat j + \alpha \hat k$
Dot product of these vectors should be equal to zero because they are perpendicular.
$\therefore \overrightarrow A \,.\,\overrightarrow B = – 8 + 12 + 8\alpha = 0$
$⇒$ $8\alpha = – 4$
$⇒$ $\alpha = – 1/2$
Standard 11
Physics
