Ha lf-lives of two radioactive elements A and B are 20 minutes and 40 minutes, respectively. Initially, the samples have equal number of nuclei. After 80 minutes, the ratio of decayed numbers of A and B nuclei will be :

The pair in which phosphorous atoms have a formal oxidation state of + 3 is :

The reaction of zinc with dilute and concentrated nitric acid, respectively produces :

Decomposition of H2O2 follows a first order reaction. In fifty minutes the concentration of H 2O2 decreases from 0.5 to…

The equilibrium constant at 298 K for a reaction A + B C + D is 100. If the initial concentration of all the four speci…

The species in which the N atom is in a state of sp hybridization is :

If 0  x < 2, then the number of real values of x, which satisfy the equation cos x + cos 2x = cos 3x + cos 4x = 0, is…

Let P be the point on the parabola, y 2 = 8x which is at a minimum distance from the centre C of the circle, x 2 + (y +…

If one of the diameters of the circle, given by the equation, x 2 + y2  4x + 6y  12 = 0, is a chord of a circle S, wh…

If a curve y = f(x) passes through the point (1, 1) and satisfies the differential equation, y(1 + xy) dx = x dy, then…

If the 2nd, 5th and 9th terms of a non-constant A.P. are in G.P., then the common ratio of this G.P. is: