All Exams Test series for 1 year @ ₹349 only
Question

For the next two (02) items that follow :
A line L passing through the point (-1, 2, -3) is perpendicular to the plane P given by $2x + 3y + z + 5 = 0$.

What are the direction ratios of a line M parallel to the plane P ?

This question was previously asked in
NDA 2 2026 GAT Question Paper (13-Sep-2026)
The correct answer is
$< 2, 2, -10 >$

The problem asks for the direction ratios of a line M that is parallel to a given plane P.

Plane P Analysis

The equation of the plane P is given as: 2 x + 3 y + z + 5 = 0 $ The normal vector n→$ to the plane P is determined by the coefficients of x, y, and z.

Normal vector n→ = <2, 3, 1>

Line M Condition

A line M is parallel to the plane P if its direction vector m→$ is perpendicular to the plane's normal vector n→.

The condition for perpendicularity is that their dot product is zero:

m→ · n→ = 0 $

Let the direction ratios of line M be <l,m,n>$. Then, the condition becomes:

< l , m , n > · < 2 , 3 , 1 > = 0 $

Or, 2l+3m+n=0$

Checking Options

We test each option's direction ratios <l,m,n>$ using the condition 2l+3m+n=0$:

  • Option 1: <-3,2,1>$
    2 ( - 3 ) + 3 ( 2 ) + 1 = - 6 + 6 + 1 = 1 ≠ 0 $
  • Option 2: <3,2,-6>$
    2 ( 3 ) + 3 ( 2 ) + ( - 6 ) = 6 + 6 - 6 = 6 ≠ 0 $
  • Option 3: <1,3,2>$
    2 ( 1 ) + 3 ( 3 ) + 2 = 2 + 9 + 2 = 13 ≠ 0 $
  • Option 4: <2,2,-10>$
    2 ( 2 ) + 3 ( 2 ) + ( - 10 ) = 4 + 6 - 10 = 10 - 10 = 0 $

Option 4 satisfies the condition m→ · n→ = 0

Conclusion

The direction ratios <2,2,-10>$ correspond to a line M parallel to the plane P.

Was this answer helpful?

Similar Questions

  1. Which of the following are the direction ratios of S?
  2. If \(p\) is the perpendicular distance from origin to the plane passing through \((1, 0, 0)\), \((0, 1, 0)\) and \((0, 0, 1)\), then what is \(3p^2\) equal to ?
  3. What is the equation of the line L ?
  4. Which of the following are the direction ratios of the line of intersection of the given planes?
  5. What is the equation of the plane \(P\)?

Important Questions from Equation in a Plane

  1. Which of the following are the direction ratios of S?
  2. If \(p\) is the perpendicular distance from origin to the plane passing through \((1, 0, 0)\), \((0, 1, 0)\) and \((0, 0, 1)\), then what is \(3p^2\) equal to ?
  3. What is the equation of the line L ?
  4. A straight line segment is 36 cm long. Points are to be marked on the line from both the end points. From each end, the first point is at a distance of 1 cm from the end, the second point is at a distance of 2 cm from the first point and the third point is at a distance of 3 cm from the second point and so on. 

    If the points on the ends are not counted and the common points are counted as one, what is the number of points?

  5. Which of the following are the direction ratios of the line of intersection of the given planes?
Need Expert Advice?
Test Series
NDA img
Defence
NDA 2026 Mock Test Series (Latest Pattern)
526 Tests 1 Tests Free
1168 Attempts
4.7(160)
English, Hindi

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App