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

Q1. The value of √(-16) is

(a) -4i

(b) 4i

(c) -2i

(d) 2i

Ans: (b) 4i

Q2. The value of √(-144) is

(a) 12i

(b) -12i

(c) ±12i

(d) None of these

Ans: a) 12i

Q3. The value of √(-25) + 3√(-4) + 2√(-9) is

(a) 13i

(b) -13i

(c) 17i

(d) -17i

Ans: (c) 17i

Q4. If z lies on |z| = 1, then 2/z lies on

(a) a circle

(b) an ellipse

(c) a straight line

(d) a parabola

Ans: a) a circle

Q5. If ω is an imaginary cube root of unity, then (1 + ω – ω²)7 equals

(a) 128 ω

(b) -128 ω

(c) 128 ω²

(d) -128 ω²

Ans: d) -128 ω²

Q6. The value of i-999 is

(a) 1

(b) -1

(c) i

(d) -i

Ans: (c) i

Q7. The curve represented by Im(z²) = k, where k is a non-zero real number, is

(a) a pair of straight line

(b) an ellipse

(c) a parabola

(d) a hyperbola

Ans: d) a hyperbola

Q8. The value of x and y if (3y – 2) + i(7 – 2x) = 0

(a) x = 7/2, y = 2/3

(b) x = 2/7, y = 2/3

(c) x = 7/2, y = 3/2

(d) x = 2/7, y = 3/2

Ans: (a) x = 7/2, y = 2/3

Q9. if x + 1/x = 1 find the value of x2000 + 1/x2000 is

(a) 0

(b) 1

(c) -1

(d) None of these

Ans: c) -1

Q10. If the cube roots of unity are 1, ω, ω², then the roots of the equation (x – 1)³ + 8 = 0 are

(a) -1, -1 + 2ω, – 1 – 2ω²

(b) – 1, -1, – 1

(c) – 1, 1 – 2ω, 1 – 2ω²

(d) – 1, 1 + 2ω, 1 + 2ω²

Ans: c) – 1, 1 – 2ω, 1 – 2ω²

Q11. The modulus of 5 + 4i is

(a) 41

(b) -41

(c) √41

(d) -√41

Ans: (c) √41