# Multiple choice (Matrix)

** Choose and write the correct option in the following question:(Class 12 matrix multiple choice question)**

**1.) If** Then **is equal to**

(a)

(b)

(c)

(d)

**Answer (d)**

**2.) If** , then if the value of α is

(a) π/6 (b) π/3

(c) π (d) 3π/2

**Answer (b)**

3.)If A and B are square matrices of the same order , then (A + B)(A – B) is equal to

(a) (b)

(c) (d)

**Answer (c)**

**4.) Total number of possible matrices of order 3×3 with each entry 2 or 0 is**

(a) 9 (b) 27

(c) 81 (d) 512

**Answer (d)**

**5.) The matrix** is a

(a) Diagonal matrix (b) Symmetric matrix

(c) Skew symmetric matrix (d) Scalar matrix

**Answer (c)**

**Assume X, Y, Z, W and P are matrices of order 2×n,3×k, 2×p, n×3 and p×k respectively. Choose the correct option in (6) and (7)**

**6.) The restriction on n, k and p so that PY + WY willbe defined are**

(a) k = 3, p = n (b) k is arbitrary, p = 2

(c) p is arbitrary, k = 3 (d) k = 2, p = 3

**Answer (a)**

**7.) If n = p then the order of the matrix 7X – 5Z is**

(a) p×2 (b) 2×n

(c) n×3 (d) p×n

**Answer (b)**

**8.) If** , Then the value of x and y is

(a) x = 3, y = 1 (b) x = 2, y = 3

(c) x = 2, y = 3 (d) x = 3, y = 3

**Answer (b)**

**9.) If A is matrix of order m×n and B is a matrix such that AB’ and B’A are both defined, the order of matrix B is**

(a) m×m (b) n×n

(c) n×m (d) m×n

**Answer (d)**

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

(a) Skew symmetric matrix (b) Null matrix

(c) Symmetric matrix (d) Unit matrix

**Answer (a)**

**11.) If** is such that , then

(a) I + α² + βγ = 0 (b) I – α² + βγ = 0

(c) I – α² – βγ = 0 (d) I + α² – βγ = 0

**Answer (c)**

**12.) A matrix** is defined by

**The number of elements in A which are more than 5 is**

(a) 3 (b) 4

(c) 5 (d) 6

**Answer (b)**

**13.) If ** , then (wher a∈ N) equals

(a)

(b)

(c)

(d)

**Answer (a)**

**14.) If A is a square matrix such that A² = I, then** is equal to

(a) A (b) I – A

(c) I + A (d) 3A

**Answer (a)**

**15.) If the matrix AB is zero, then**

(a) It is not necessary that either A = O or B = O

(b) A = O or B = O

(c) A = O and B = O

(d) All the statement are wrong

**Answer (a)**

**16.) If** and , then

(a) Only AB is defined (b) Only BA is defined

(c) AB and BA both are defined (d) AB and BA are not defined.

**Answer (c)**

**17.) If A and B are symmetric matrices of the same order, then (AB’- BA’) is a**

(a) Skew symmetric matrix (b) Null matrix

(c) Symmetric matrix (d) None of these

**Answer (a)**

**18.) The matrix** is

(a) A Skew symmetric matrix (b) Null matrix

(c) A diagonal matrix (d) An upper triangular matrix

**Answer (a)**

**19.) If A and B are two matrices of the order 3×m and 3×n respectively and m = n, then the order of matrix (5A – 2B) is**

(a) m×3 (b) 3×3

(c) m×n (d) 3×n

**Answer (d)**

**20.) If** **and A = A’, then**

(a) x = 0, y = 5 (b) x + y = 5

(c) x = y (d) None of these

**Answer (c)**