ISRO | ISRO CS 2017 | Question 10

Tutorials
- Algorithms
- Data Structures
  - Arrays
  - Linked List
  - Stack
  - Queue
  - Binary Tree
  - Binary Search Tree
  - Heap
  - Hashing
  - Graph
  - Advanced Data Structure
  - Matrix
  - Strings
  - All Data Structures
- Languages
  - C
  - C++
  - Java
  - Python
  - C#
  - Javascript
  - jQuery
  - SQL
  - PHP
  - Scala
  - Perl
  - Go Language
  - HTML
  - CSS
  - Kotlin
- Interview Corner
- GATE
- ISRO CS
- UGC NET CS
- CS Subjects
- Web Technologies
  - HTML
  - CSS
  - Javascript
  - jQuery
  - PHP
Student
Jobs
- Apply for Jobs
- Post a Job
Courses

Write

Come write articles for us

Practice

Learn and code with experts

IDE

Test and compile your codes here

Jobs

Come get hired with us

Last Updated : 22 Mar, 2018

If vectors $\vec{a}=2\hat{i}+\lambda \hat{j}+\hat{k }$ and $\vec{b}=\hat{i}-2 \hat{j}+3\hat{k }$ are perpendicular to each other, then value of λ is

(A) 2/5
(B) 2
(C) 3
(D) 5/2

Answer: (D)

Explanation: Given, vectors $\vec{a}=2\hat{i}+\lambda \hat{j}+\hat{k }$ and $\vec{b}=\hat{i}-2 \hat{j}+3\hat{k }$ are perpendicular to each other, so $\vec{a} \dot \vec{b} = 0$

$\vec{a} \dot \vec{b} = 2\times 1 - 2\times \lambda + 3\times 1 = 0$

$2\times 1 - 2\times \lambda + 3\times 1 = 0$

$-2\lambda = -5$

$\lambda = 5 / 2$

So, option (D) is correct.

Quiz of this Question

My Personal Notes

first_page Previous

ISRO | ISRO CS 2009 | Question 45

Next last_page

ISRO | ISRO CS 2017 | Question 17

Related Articles