 # NCERT Solution Class 12 Chapter 10- Vector Algebra Exercise 10.2

The Exercise 10.2 of NCERT Solutions for Class 12 Maths Chapter 10- Vector Algebra is based on the following topics:

2. Multiplication of a Vector by a Scalar
1. Components of a vector
2. Vector joining two points
3. Section formula

All these topics can be understood thoroughly by solving the problems given in this exercise. The solutions of all the problems of this exercise is given here.

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### Access Answers of Maths NCERT Class 12 Maths Chapter 10- Vector Algebra Exercise 10.2 Page Number 440        ### Access other exercises of Class 12 Maths Chapter 10

Exercise 10.1 Solutions 5 Questions

Exercise 10.3 Solutions 18 Questions

Exercise 10.4 Solutions 12 Questions

Miscellaneous Exercise On Chapter 10 Solutions 19 Questions

#### Access Answers of Maths NCERT Class 12 Chapter 10.2

1. Compute the magnitude of the following vectors: Solution:

Given vectors are: 2. Write two different vectors having same magnitude.

Solution: 3. Write two different vectors having same direction.

Solution:  4. Find the values of x and y so that the vectors are equal

Solution:

Given vectors will be equal only if their corresponding components are equal.

Thus, the required values of x and y are 2 and 3 respectively.

5. Find the scalar and vector components of the vector with initial point (2, 1) and terminal point (–5, 7).

Solution:

The vector with initial point P (2, 1) and terminal point Q (–5, 7) can be shown as,  Thus, the required scalar components are –7 and 6 while the vector components are 6. Find the sum of the vectors

Solution:  7. Find the unit vector in the direction of the vector

Solution:  8. Find the unit vector in the direction of vector , where P and Q are the points

(1, 2, 3) and (4, 5, 6), respectively

Solution: 9. For given vectors, and , find the unit vector in the direction of the vector Solution: 10. Find a vector in the direction of vector which has magnitude 8 units.

Solution:  11. Show that the vectors are collinear.

Solution: Therefore, the given vectors are collinear.

12. Find the direction cosines of the vector Solution: 13. Find the direction cosines of the vector joining the points A (1, 2, –3) and

B (–1, –2, 1) directed from A to B.

Solution:

Given points are A (1, 2, –3) and B (–1, –2, 1).

Now, 14. Show that the vector is equally inclined to the axes OX, OY, and OZ.

Solution: 15. Find the position vector of a point R which divides the line joining two points P and Q whose position vectors are respectively, in the ration 2:1

(i) internally

(ii) externally

Solution:

The position vector of point R dividing the line segment joining two points

P and Q in the ratio m: is given by:  16. Find the position vector of the mid point of the vector joining the points P (2, 3, 4) and Q (4, 1, – 2).

Solution:

The position vector of mid-point R of the vector joining points P (2, 3, 4) and Q (4, 1, – 2) is given by, 17. Show that the points A, B and C with position vectors,  respectively form the vertices of a right angled triangle.

Solution:

Given position vectors of points A, B, and C are: 18. In triangle ABC (Fig 10.18) which of the following is not true: Solution: 19. If are two collinear vectors, then which of the following are incorrect:

A. , for some scalar λ

B. C. the respective components of are proportional

D. both the vectors have same direction, but different magnitudes

Solution:  