# TOP 100+ MCQ On Matrices Class 12 PDF Download

These MCQ On Matrices Class 12 PDFs are most important for your upcoming examinations including JEE Main & JEE Advanced. These MCQ On Matrices Class 12 will help you to score good marks in your exams by helping you to prepare the concepts better and hence, help you to understand the concepts more clearly.

## MCQ On Matrices Class 12 PDF Download

1. If A and B are matrices of the same order, then (AB’ – BA’) is a

(A) skew-symmetric matrix

(B) null matrix

(C) symmetric matrix

(D) unit matrix

Answer: skew symmetric matrix

2. A square matrix A = [aij]n×nis called a diagonal matrix if aij = 0 for

(A) i = j

(B) i < j

(C) i > j

(D) i ≠ j

Answer: i ≠ j

3. If A and B are 2 × 2 matrices, then which of the following is true?

(A) (A + B)² = A² + B² + 2AB

(B) (A – B)² = A² + B² – 2AB

(C) (A – B)(A + B) = A² + AB – BA – B²

(D) (A + B) (A – B) = A² – B²

Answer: (A – B)(A + B) = A² + AB – BA – B²

4. A = [aij]m×nis a square matrix if

(A) m = n

(B) m < n

(C) m > n

(D) None of these

Answer: m = n

5. If P is of order 2 x 3 and Q is of order 3 x 2, then PQ is of order

(A) 2 x 3

(B) 2 x 2

(C) 3 x 2

(D) 3 x 3

Answer: 2 x 2

6. If a matrix has 24 elements then the number of possible orders it can have, is

(A) 6

(B) 8

(C) 12

(D) 16

7. If A and B are two matrices such that both AB and BA are defined, then

(A) A and B can be any two matrices.

(B) A and B are not square matrices not necessarily of the same order.

(C) A and B are square matrices of the same order.

(D) a number of columns of A = number of rows of B.

Answer: A and B are not square matrices not necessarily of the same order.

8. If A is an orthogonal matrix then ATis a/an

(A) identity matrix

(B) null matrix

(C) orthogonal matrix

(D) scalar matrix

9. If A = [3 4 7 -1] [1 6 7 2] [9 8 6 4] then the order of the matrix is

(A) 4 * 3

(B) 3 * 4

(C) 3 * 3

(D) 4 * 4

Answer: 3 * 4

10. If 2[3 4] + [1 y] = [7 0] [5 x] [0 1] [10 5] then the value of x – y is

(A) 8

(B) 10

(C) -8

(D) -10

11. If A = [ 2 -3 -1 4] then the matrix B such that 2A + 3B = 0 is

(A) [4/3 2 2/3 -8/3]

(B) [-4/3 2 2/3 8/3]

(C) [-4/3 2 2/3 -8/3]

(D) [-4/3 2 -2/3 -8/3]

Answer: [-4/3 2 2/3 -8/3]

12. If A is a skew-symmetric matrix of order 3, then the value of determinant A is

(A) 0

(B) 1

(C) -1

(D) None of these

13. If A = then find value of α for which A² = B is

(A) 1

(B) -1

(C) 4

(D) None of these

Answer: None of these

14. If A = then A8– 28 (A – I)

(A) I – A

(B) A

(C) I + A

(D) A – 2I

Answer: 2I – A

15. If A = then A2– 5A is equal to

(A) 2I

(B) 3I

(C) -2I

(D) null matrix

16. If A = B = then A – B equal to

(A) I

(B) O

(C) 1

(D) 3/2 |

17. If then find the value of x, y, z and w respectively

(A) 2, 2, 3, 4

(B) 2, 3, 1, 2

(C) 3, 3, 0, 1

(D) None of these

Answer: 2, 2, 3, 4

18. If A = then the value of x is

(A) 3

(B) ±3

(C) ±6

(D) 6

19. If A is a square matrix, then A is symmetric iff

(A) A2 = A

(B) A2 = I

(C) At = A

(D) At = – A

Answer: At = A

20. If A is any square matrix, then

(A) A + At is symmetric

(B) A – At is symmetric

(C) AAt is scew symmetric

(D) none of these

Answer: A + At is symmetric