Wbjee

Out of the following outer electronic configurations of atoms, the highest oxidation state is achieved by which one?

(A) (n –1)d⁸ns² 

(B) (n –1)d⁵ns² 

(C) (n –1)d³ns² 

(D) (n –1)d⁵ns¹

The correct order of reactivity for the addition reaction of the following carbonyl compounds with ethylmagnesium iodide is

(A) I > III > II > IV 

(B) IV > III > II > I 

(C) I > II > IV > III 

(D) III > II > I > IV

There is a small air bubble at the centre of a solid glass sphere of radius ‘r’ and refractive index ‘Ω‘. What will be the apparent distance of the bubble from the centre of the sphere, when viewed from outside?

(A) r

(B) r/μ

(C) r(1 – 1/μ)

(D) Zero

On the occasion of Dipawali festival each student of a class sends greeting cards to others. If there are 20 students in the class, the number of cards send by students is 

(A) ²⁰C₂ 

(B) ²⁰P₂ 

(C) 2 × ²⁰C₂ 

(D) 2 × ²⁰P₂

A compound formed by elements X and Y crystallizes in the cubic structure, where X atoms are at the corners of a cube and Y atoms are at the centres of the body. The formula of the compound is : 

(A) XY 

(B) XY₂ 

(C) X₂Y₃ 

(D) XY₃

The number (101)¹⁰⁰ – 1 is divisible by 

(A) 10⁴ 

(B) 10⁶ 

(C) 10⁸ 

(D) 10¹²

The intensity of a sound appears to an observer to be periodic. Which of the following can be the cause of it? 

(A) The intensity of the source is periodic. 

(B) The source is moving towards the observer. 

(C) The observer is moving away from the source. 

(D) The source is producing a sound composed of two nearby frequencies.

How the linear velocity ‘v’ of an electron in the Bohr orbit is related to its quantum number ‘n’?

(A) v ∝ 1/n

(B) v ∝ 1/n²

(C) v ∝ 1/√n

(D) v ∝ n

Silver chloride dissolves in excess of ammonium hydroxide solution. The cation present in the resulting solution is 

(A) [Ag(NH₃)₆]⁺ 

(B) [Ag(NH₃)₄]⁺ 

(C) Ag⁺ 

(D) [Ag(NH₃)₂]⁺

Let f : [a, b] → R be such that f is differentiable in (a, b), f is continuous at x = a and x = b and moreover f(a) = 0 = f(b). Then 

(A) there exists at least one point c in (a, b) such that f'(c) = f(c) 

(B) f'(x) = f(x) does not hold at any point in (a, b) 

(C) at every point of (a, b), f'(x) > f(x) 

(D) at every point of (a, b), f'(x) < f(x)