Question

The value of λ for which the two vectors `2hati - hatj + 2hatk` and `3hati + λhatj + hatk` are perpendicular is ______.

Options

• 2

• 4

• 6

• 8

Answer 1

The value of λ for which the two vectors `2hati - hatj + 2hatk` and `3hati + lambdahatj + hatk` are perpendicular is 8.

Explanation:

Dot product of two mutually perpendicular vectors is zero.

`\implies` 2 × 3 + (–1)λ + 2 × 1 = 0

`\implies` λ = 8.