

NCERT Solutions for Class 12 Maths Chapter 10 Exercise 10.4 (Vector Algebra): NCERT Solutions for Class 12 Maths Chapter 10 Exercise 10.4 are all about working with vectors. Vectors are used to represent quantities that have both magnitude and direction, like forces or velocities. In this exercise, you'll learn how to multiply vectors both in a regular way and in a special way called dot product and cross product. These operations are useful in geometry and physics to solve problems involving distances, angles, forces, and motion. The solutions provided in this exercise help you understand these concepts better and solve problems step by step. By practicing with these solutions, you'll become more confident in dealing with vector problems and improve your math skills.
NCERT Solutions for Class 12 Maths Chapter 10 Exercise 10.4 of Vector Algebra is prepared by the academic team of Physics Wallah. We have prepared NCERT Solutions for all exercise of Chapter 10. Given below are step-by-step solutions to all questions given in the NCERT Solutions for Class 12 Maths Chapter 10 Exercise 10.4.
NCERT Solutions for Class 12 Maths Chapter 10 Miscellaneous Exercise
x
| if
Solution :
We have,
NCERT Solutions for Class 12 Maths Chapter 10 Exercise 10.1
Question 2. Find a unit vector perpendicular to each of the vectors
Solution :
We have
NCERT Solutions for Class 12 Maths Chapter 10 Exercise 10.2
Question 3. If a unit vector
makes an angle π/3 with
and an acute angle θ with
then find θ and hence, the components of
.
Solution :
Let unit vector
have (
a
1
,
a
2
,
a
3
) components.
NCERT Solutions for Class 12 Maths Chapter 10 Exercise 10.3
Question 4. Show that
Solution :
Question 5. Find λ and μ if
Solution :
Question
6. Given that
.
= 0 and
x
= 0 What can you conclude about the vectors
and
?
Solution :
.
= 0
Then,
(i)
Either |
| = 0 or |
| = 0, or
⊥
(in case
and
are non - zero)
x
= 0
(ii)
Either |
| = 0 or |
| = 0 or
||
(in case
and
are non - zero)
But,
and
cannot be perpendicular and parallel simultaneously.
Hence |
| = 0 or |
| =0.
Question
7. Let the vectors
,
,
be given as
then show that
Solution :
We have
,
Hence, the given result is proved.
Question
8. It either
= 0 and
= 0 then
x
= 0 Is the converse true? Justify your answer with an example.
Solution :
Take any parallel non-zero vectors so that
x
= 0
Hence, the converse of the given statement need not be true.
Question
9. Find the area of the triangle with vertices A (1, 1, 2), B (2, 3, 5) and C (1, 5, 5).
Solution :
The vertices of triangle ABC are given as A (1, 1, 2), B (2, 3, 5), and
C (1, 5, 5).
The adjacent sides
and
of ΔABC are given as:
Hence, the area of ΔABC is √61/2 sq. units.
Question
10. Find the area of the parallelogram whose adjacent sides are determined by the vectors
Solution :
The area of the parallelogram whose adjacent sides are
and
is |
x
|.
Adjacent sides are given as:
Hence, the area of the given parallelogram is 15√2 sq. units.
Question
11. Let the vectors
and
such that |
| = 3 and |
| = √2/3 then
x
is a unit vector, if the angle between
and
is:
(A) π/6
(B) π/4
(C) π/3
(D) π/2
Solution :
It is given that |
| = 3 and |
| = √2/3
We know that
x
= |
||
|sin
θ
, where n is a unit vector perpendicular to both
and
and
θ
is the angle between
and
.
Now,
x
is a unit vector if
|
x
| = 1
Therefore, option (B) is correct.
Question
12. Area of a rectangle having vertices A, B, C and D with position vectors
respectively is:
(A) 1/2
(B) 1
(C) 2
(D) 4
Solution :
The position vectors of vertices A, B, C, and D of rectangle ABCD are given as:
The adjacent sides
and
of the given rectangle are given as:
Now, it is known that the area of a parallelogram whose adjacent sides are
and
is
|
x
|
.
Hence, the area of the given rectangle is |
x
| = 2 sq. units.
Therefore, option (C) is correct.
