List of top Questions asked in WBJEE- 2008

Unusual high boiling point of water is result of

The electronic configuration $1 s^{2},\, 2 s^{2} 2 p^{6},\, 3 s^{2} 3 p^{6} 3 d^{9}$ represents a

Benzoylation of phenol in alkaline medium is known as

$2N HCl$ solution will have same molar concentration as a

The $IUPAC$ name of $CH_{3}-CH=CH-C \equiv CH$ is

Addition of sodium acetate to $0.1 \,M$ acetic acid will cause

A hollow cylinder with both sides open generates a frequency $ f $ in air. When the cylinder vertically immersed into water by half its length the frequency will be

Two springs are joined and attached to a mass of $16\, kg$. The system is then suspended vertically from a rigid support. The spring constant of the two springs are $ {{k}_{1}} $ and $ {{k}_{2}} $ respectively. The period of vertical oscillations of the system will be

The major product $P$ in the following reaction is $ C{{H}_{3}}-CH=C{{H}_{2}}\xrightarrow[Peroxide]{HI}P $

The equation of a progressive wave can be given by $ y=15 $ $ \sin (660\pi t-0.02\pi x)\,cm. $ The frequency of the wave is

A rocket of mass $100 \,kg$ burns $0.1\, kg$ of fuel per sec. If velocity of exhaust gas is $1 \,km/s^{-1}$, then it lifts with an acceleration of

A beaker of radius $15\, cm$ is filled with a liquid of surface tension $0.75\, N/m$. Force across an imaginary diameter on the surface of the liquid is

Force required to move a mass of $1 \,kg$ at rest on a horizontal rough plane ( $ \mu =0.1 $ and $ g=9.8\,m{{s}^{2}} $ ) is

If the $m^{th}$ term and the nth term of an $AP$ are respectively $\frac{1}{n}$ and $\frac{1}{m}$, then the $(mn )^{th}$ term of the $AP$ is

The coefficient of $ x^{-10}$ in $\left(x^{2} - \frac{1}{x^{3}}\right)^{10}$ is

The value of $\left(1-\omega+\omega^{2}\right)^{5} + \left(1+\omega -\omega^{2}\right)^{5}, $ where $\omega$ and $\omega^2$ are the complex cube roots of unity, is

The number of ways four boys can be seated around a round-table in four chairs of different colours is

The function $f(x ) = xe^{1-x}$ is

In a given shell the order of screening effect is

In transforming $0.01$ mole of $PbS$ to $PbSO _{4}$, the volume of ' $10$ volume' $H _{2} O _{2}$ required will be

A shell of mass $10\, kg$ is moving with a velocity of $ 10\,ms^{-1}$ when it blasts and forms two parts of mass $9 \,kg$ and $1 \,kg$ respectively. If the $1^{st}$ mass is stationary, the velocity of the $ 2^{nd} $ is

The differential equation of the family of curves $y = e^{2x} (a \,\cos\, x + b \,\sin\, x)$, where $a$ and $b$ are arbitrary constants, is given by

If the matrix $\begin{bmatrix}a&b\\ c&d\end{bmatrix}$ is commutative with the matrix $\begin{bmatrix}1&1\\ 0&1\end{bmatrix}$, then

A bullet emerge from a barrel of length $1.2\, m$ with a speed of $640\, ms ^{-1}$. Assuming constant acceleration, the approximate time that it spends in the barrel after the gun is fired is

A battery of e. m. f. $E$ and internal resistance $r$ is connected to an external resistance $R$ the condition for maximum power transfer is