If `|z|=2` and locus of `5z-1` is the circle having radius a and `z_1^2+z_2^2-2z_1z_2 cos theta=0, then |z_1|:|z_2|=` (A) a (B) 2a (C) `a/10` (D) none of these

If |z| = 2 and the locus of 5z-1 is the circle having radius 'a' and z_1^2 + z_2^2 - 2 z_1 z_2 cos theta = 0 then |z_1| : |z_2| =

If the point representing the complex number z_alpha is a point on or inside the circle having centre (0+i0) and radius alpha then maximum value of |z_1+z_2+……+z_n|= (A) (n(n+3))/2 (B) (n(n+1))/2 (C) (n(n-1))/2 (D) none of these

The complex numbers z_1, z_2 and the origin form an equilateral triangle only if (A) z_1^2+z_2^2-z_1z_2=0 (B) z_1+z_2=z_1z_2 (C) z_1^2-z_2^2=z_1z_2 (D) none of these

The points A(z_1), B(z_2) and C(z_3) form an isosceles triangle in the Argand plane right angled at B, then (z_1-z_2)/(z_3-z_2) can be (A) 1 (B) -1 (C) -i (D) none of these

If a m p(z_1z_2)=0a n d|z_1|=|z_2|=1,t h e n z_1+z_2=0 b. z_1z_2=1 c. z_1=z _2 d. none of these

If |z_1|=|z_2| then z_1/z_2+z_2/z_1= (A) 2costheta (B) -2costheta (C) 2sintheta (D) -2sintheta

If |z_1/z_2|=1 and arg (z_1z_2)=0 , then a. z_1 = z_2 b. |z_2|^2 = z_1*z_2 c. z_1*z_2 = 1 d. none of these

If |z_1+z_2|=|z_1-z_2| and |z_1|=|z_2|, then (A) z_1=+-iz_2 (B) z_1=z_2 (C) z_=-z_2 (D) z_2=+-iz_1

If 2z_1-3z_2 + z_3=0 , then z_1, z_2 and z_3 are represented by

If z_1 and z_2 are complex numbers such that |z_1-z_2|=|z_1+z_2| and A and B re the points representing z_1 and z_2 then the orthocentre of /_\OAB, where O is the origin is (A) (z_1+z_2)/2 (B) 0 (C) (z_1-z_2)/2 (D) none of these