1. If the area of the triangle on the complex plane formed by the points z, iz and z + iz is 50 square units, then |z| is

(A) 5

(B) 10

(C) 15

(D) None of these

2. If z = x + iy and w = 1 – iz / z – i , then | w | = 1 implies that, in the complex plane,

(A) z lies on the imaginary

(B) z lies on the real axis

(C) z lies on the unit circle

(D) None of these

Answer: z lies on the real axis

3. The argument of (1 – i√3)/(1 + i√3) is

(A) π/3

(B) 2π/3

(C) 7π/3

(D) 4π/3

4. The roots of the equation x2 + x + 1 = 0 is

(A) {1 ± i√3}/2

(B) {-1 ± i√3}/2

(C) {i ± √3}/2

(D) {-i ± √3}/2

5. The value of i + i2 + i3 + i4 is

(A) 0

(B) 1

(C) -1

(D) 2i

6. If α is cube root of unity, then for n ∈ N, the value of α3n + 1 + α3n + 5 is

(A) -1

(B) 0

(C) 1

(D) 3

7. The inequality | z – 2 | < | z – 4 | represents the region given by

(A) Re (z) > 0

(B) Re (z) < 3

(C) Re (z) > 2

(D) none of these

8. Let z = a + ib and if |z| = 0 then

(A) Real(z) = 0

(B) Imaginary(z) = 0

(C) Real(z) = Imaginary(z) = 0

(D) None of these

Answer: Real(z) = Imaginary(z) = 0

9. The equation whose roots are 7i and 2i is

(A) x2 + (9i)x – 14 = 0

(B) x2 – (9i)x + 14 = 0

(C) x2 – (9i)x – 14 = 0

(D) x2 + (9i)x + 14 = 0

Answer: x2 – (9i)x – 14 = 0

10. The locus of the point z satisfying Re(z2 ) = 0 is

(A) A pair of striaght line

(B) a circle

(C) a rectangular hyperbola

(D) None of these

Answer: A pair of striaght line

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Categories: Mathematics Class-11