List of top Questions asked in WBJEE

The value of cos 15° – sin 15° is

The following graph shows how T1/2(half-life) of a reactant R changes with the initial reactant concentration a0.

The order of the reaction will be : 

Which statement is incorrect 

For the Paschen series the values of n1 and n2 in the expression $$\mathrm{\Delta }E=Rhc(\frac{1}{n_1^2}-\frac{1}{n_2^2})$$

The time taken for 10% completion of a first order reactin is 20 mins. Then, for 19%  completion, the reaction will take 

Hybridisation of central atom in NF3 is 

Under which of the following condition is the relation valid $\mathrm{\Delta }H=\mathrm{\Delta }E+P\mathrm{\Delta }V$ for a closed system?

Equal volumes of molar hydrochloric acid and sulphuric acid are neutralised by dilute NaOH solution and x kcal and y kcal of heat are liberated respectively.  Which of the following is true?

For the reaction $S{O}_2+\frac{1}{2}{O}_2=S{O}_3,$ if we write $K_p=K_c(RT{)}^x,$ then $x$ becomes

The general solution of the differential equation $\frac{d^{2}y}{d{x}^2}+8\frac{dy}{dx}+16y=0$ is

The number of solutions of log2(x – 1) = 2 log2(x – 3) is

$\sum _{r=0}^{m}n+r{c}_r$ is equal to

The locus of the centre of a circle which passes through two variable points (a, 0), (–a, 0) is 

At temperature 300 K for reaction  C2H4(g) + 3O2(g)→ 2CO2(g) + 2H2O(g); ΔH = −336.2 kcal.  The approximate value of ΔU  at 300 K for the same reaction (R = 2 cal degree^{− 1} mol^{− 1}) will be-

If nt number of radioatoms are present at time t, the following expression will be a constant : 

A compound is formed by substitution of two chlorine for two hydrogens in propane. The number of possible isomeric compounds is 

Ethelene can be separated from acetylene by passing the mixture through : 

Atoms in a P4 molecule of white phosphorus are arranged regularly in the following way : 

Of the following acids the one which has the capability to form complex compound and also possesses oxidizing and reducing properties is:

Out of the 20 amino acids, only two of them contain sulfur. Those two amino acids are:

If $y=2x^3-2x^2+3x-5$, then for $x=2$ and $\mathrm{\Delta }x=0.1$ value of $\mathrm{\Delta }y$ is:

The derivative of f(tan x) w.r.t. g(sec x) at x = π/4 where f`(1) = 2 and g`(√2) =4, is

The general solution of the differential equation ${\log }_e\left(\frac{dy}{dx}\right)=x+y$ is

The approximate value of 5√33 correct to 4 decimal places is