JOIN ADRE 2.0 Telegram Group

NCERT Solutions for class 11 Maths | Chapter 5 - Complex Numbers and Quadratic Equations

Questions
1 If arg (z) < 0, then arg (-z) – arg (z) =
A π
B -π
C -π/2
D π/2

Answer:π
2 The curve represented by Im(z²) = k, where k is a non-zero real number, is
A a pair of striaght line
B an ellipse
C a parabola
D a hyperbola

Answer: a hyperbola
Advertisement
Article and Schedule Quiz Start Test!

DOWNLOAD CURRENT AFFAIRS PDF FROM APP

3 The value of i-999 is
A 1
B -1
C i
D -i

Answer:i
4 The least value of n for which {(1 + i)/(1 – i)}n is real, is
A 1
B 2
C 3
D 4

Answer:2
5 The value of √(-16) is
A -4i
B 4i
C -2i
D 2i

Answer:4i
6 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

Answer:-128 ω²
7 Let z be a complex number such that |z| = 4 and arg(z) = 5π/6, then z =
A -2√3 + 2i
B 2√3 + 2i
C 2√3 – 2i
D -√3 + i

Answer:-2√3 + 2i
8 The value of √(-25) + 3√(-4) + 2√(-9) is
A 13i
B -13i
C 17i
D -17i

Answer:17i
9 if z lies on |z| = 1, then 2/z lies on
A a circle
B an ellipse
C a straight line
D a parabola

Answer:a circle
10 The value of √(-144) is
A 12i
B -12i
C ±12i
D None of these

Answer:12i
11 If {(1 + i)/(1 – i)}n = 1 then the least value of n is
A 1
B 2
C 3
D 4

Answer:4
12 (1 – w + w²)×(1 – w² + w4)×(1 – w4 + w8) × …………… to 2n factors is equal to
A 2n
B 22n
C 23n
D 24n

Answer:22n
13 The value of √(-144) is
A 12i
B -12i
C ±12i
D None of these

Answer:12i
14 The modulus of 5 + 4i is
A 41
B -41
C √41
D -√41

Answer:√41
15 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

Answer:– 1, 1 – 2ω, 1 – 2ω²
16 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

Answer:x = 7/2, y = 2/3
17 Find real θ such that (3 + 2i × sin θ)/(1 – 2i × sin θ) is imaginary
A θ = nπ ± π/2 where n is an integer
B θ = nπ ± π/3 where n is an integer
C θ = nπ ± π/4 where n is an integer
D None of these

Answer:θ = nπ ± π/3 where n is an integer
18 if x + 1/x = 1 find the value of x2000 + 1/x2000 is
A 0
B 1
C -1
D None of these

Answer:-1
19 Let z1 and z2 be two roots of the equation z² + az + b = 0, z being complex. Further assume that the origin, z1 and z1 form an equilateral triangle. Then
A a² = b
B a² = 2b
C a² = 3b
D a² = 3b

Answer:a² = 3b
20 The complex numbers sin x + i cos 2x are conjugate to each other for
A x = nπ
B x = 0
C x = (n + 1/2) π
D no value of x

Answer:no value of x

ADRE 2.0 FULL LENGTH MOCK TEST

Take Mock Tests

Missiles Mock Test Start Test!
SSC MTS Mock Test Start Test
IBPS CLERK MOCK TEST Start Test
SSC MTS 2022 JULY 26 Shift 1 (ENGLISH) Start Test!
SSC GD Previous Year Paper 2021 Nov 17 Shift - I (Hindi) Start Test!
SSC CGL Tier - 1 PYP 2022 April 21 Shift- 1 (ENGLISH) Start Test!
MPSC PAPER I MOCK TEST 1 (ENGLISH) Start Test!
IB Security Assistant Mock test 1 (english) Start Test!
UP POLICE CONSTABLE MOCK TEST 1 Start Test!
DELHI POLICE CONSTABLE MOCK TEST 1 (HINDI) Start Test!

Chapters

Advertisement
Assam Direct Recruitment Test Series