MCQs Questions for Class 11 Maths Chapter 5 Complex Numbers and Quadratic Equations

# MCQs Questions for Class 11 Maths Chapter 5 Complex Numbers and Quadratic Equations

## MCQs Questions for Class 11 Maths Chapter 5 Complex Numbers and Quadratic Equations

In this 21st century, Multiple Choice Questions (MCQs) play a vital role to prepare for a competitive examination. CBSE board has also brought a major change in its board exam patterns. In most of the competitive examinations, only MCQ Questions are asked.

In future, if you want to prepare for competitive examination, then you should focus on the MCQs questions. Thus, let’s solve these MCQs questions to make our foundation strong.

In this post, you will find 15 MCQs questions for class 11 maths chapter 5 complex numbers and quadratic equations.

## MCQs Questions for Class 11 Maths Chapter 5 Complex Numbers and Quadratic Equations

1. The value of √(-81) is
(a) -9i
(b) 9i
(c) -3i
(d) 3i

2. In a complex number, z = 4 + i, what is the real part?
(a) 4
(b) i
(c) 1
(d) 4 + i

3. The value of √(-144) is
(a) 12i
(b) -12i
(c) ±12i
(d) None of these

4. If (x + 3) + i(y – 2) = 5 + 2i, then find the values of x and y.
(a) x = 8 and y = 4
(b) x = 2 and y = 4
(c) x = 2 and y = 0
(d) x = 8 and y = 0

5. If z lies on |z| = 1, then 2/z lies on
(a) a circle
(b) an ellipse
(c) a straight line
(d) a parabola

6.  If z1 = 2 + 3i and z2 = 5 + 2i, then find the sum of two complex numbers.
(a) 4 + 8i
(b) 3 – I
(c) 7 + 5i
(d) 7 – 5i

7. If Ï‰ is an imaginary cube root of unity, then (1 + Ï‰ – Ï‰²)7 equals
(a) 128 Ï‰
(b) -128 Ï‰
(c) 128 Ï‰²
(d) -128 Ï‰²

8. -z is _________________ for the complex number z.
(c) multiplicative identity element
(d) multiplicative inverse

9. The least value of n for which {(1 + i)/(1 – i)}n is real, is
(a) 1
(b) 2
(c) 3
(d) 4

10. 1/z is _________________ for complex number z.
(c) multiplicative identity element
(d) multiplicative inverse

11. The value of i-999 is
(a) 1
(b) -1
(c) i
(d) -i

12. If z1 = 8 + 5i and z2 = 3 + 6i, then find the value of z1 – z2.
(a) -5 + i
(b) 5 – i
(c) 5 + i
(d) 5 – 5i

13. The complex numbers sin x + i cos 2x and sin x i cos 2x are conjugate to each other for
(a) x = nÏ€
(b) x = 0
(c) x = (n + 1/2) Ï€
(d) no value of x

14.  In the complex number, z = 5 + 2i, what is the imaginary part?
(a) 5
(b) 2i
(c) 5 + 2
(d) 5 + 2i