List of top Questions asked in WBJEE

The de-Broglie wavelength of a moving bus with speed \( v \) is \( \lambda \). Some passengers left the bus at a stop. Now, when the bus moves with twice of its initial speed, its kinetic energy is found to be twice of its initial value. What is the de-Broglie wavelength of the bus now?
Six vectors \( \mathbf{a}, \mathbf{b}, \mathbf{c}, \mathbf{d}, \mathbf{e}, \mathbf{f} \) have the magnitudes and directions indicated in the figure. Which of the following statements is true?
The compound(s) showing optical activity is/are

Which of the following statement(s) is/are correct about the given compound?

X is an extensive property and x is an intensive property of a thermodynamic system. Which of the following statement(s) is (are) correct?

The major product 'P' and 'Q' in the above reactions are

Consider the following gas phase dissociation, PCl$_5$(g) $\rightleftharpoons$ PCl$_3$(g) + Cl$_2$(g) with equilibrium constant K$_p$ at a particular temperature and at pressure P. The degree of dissociation ($\alpha$) for PCl$_5$(g) is
PCl$_5$(g) $\rightleftharpoons$ PCl$_3$(g) + Cl$_2$(g)

The common stable oxidation states of Eu and Gd are respectively

Identify the major product (G) in the following reaction

In the nuclear reaction \( \mathrm{^{10}_{5}B} + \mathrm{^{4}_{2}He} \rightarrow X + \mathrm{^{1}_{0}n} \), X represents:
Adiabatic free expansion of an ideal gas must be: \} \begin{tabular}{ll} (A) Isobaric & (B) Isochoric
(C) Isothermal & (D) Isoentropic
\end{tabular}
Equal volumes of two solutions A and B of a strong acid having pH = 6.0 and pH = 4.0 respectively are mixed together to form a new solution. The pH of the new solution will be in the range:

Kjeldahl's method cannot be used for the estimation of nitrogen in which compound?
 

(A)(B)(C)(D)
NH2-CH2-COOHC6H5-NH2C6H5-N=N-C6H5O2N-C6H4-NO2

Which one among the following compounds will most readily be dehydrated under acidic condition?
 

(A)(B)(C)(D)
CH3-CH2-CH2-OHCH3-CH(CH3)-CH2-OHCH3-CH2-CH(CH3)-OHC(CH3)(CH3)-CH2-OH
(1° alcohol)(2° alcohol)(2° alcohol)(3° alcohol)

For a chemical reaction, half-life period \(t_{1/2}\) is 10 minutes. How much reactant will be left after 20 minutes if one starts with 100 moles of reactant and the order of the reaction is:

P and Q combine to form two compounds PQ2 and PQ3. If 1 g of PQ2 is dissolved in 51 g of benzene, the depression of freezing point becomes 0.8°C. On the other hand, if 1 g of PQ3 is dissolved in 51 g of benzene, the depression of freezing point becomes 0.625°C. The atomic mass of P and Q are (Kf of benzene = 5.1 K·kg/mol):
If three elements A, B, C crystallize in a cubic solid lattice with B atoms at the cubic centres, C atoms at the centre of edges, and A atoms at the corners, then the formula of the compound is:
Increasing order of solubility of AgCl in:
  • (i) H2O
  • (ii) 1M NaCl (aq)
  • (iii) 1M CaCl2 (aq)
  • (iv) 1M NaNO3 (aq)
If the dimensions of length are expressed as \( G^x C^y h^z \), where \( G \), \( C \), and \( h \) are the universal gravitational constant, speed of light, and Planck's constant respectively, then:
A wave disturbance in a medium is described by \[ y(x,t) = 0.02 \cos\left(50 \pi t + \frac{\pi}{2}\right) \cos(10 \pi x) \] where \( x \) and \( y \) are in meters and \( t \) is in seconds. Which statement(s) is/are correct?
Let \( \bar{V} \), \( V_{\text{rms}} \), \( V_p \) denote the mean speed, root mean square speed, and most probable speed of the molecules of mass \( m \) in an ideal monoatomic gas at absolute temperature \( T \) Kelvin. Which statement(s) is/are correct?
Let the binding energy per nucleon of a nucleus be denoted by \( E_{\text{b/n}} \), and the radius of the nucleus is denoted by \( r \). If the mass numbers of nuclei A and B are 64 and 125 respectively, then:
A piece of granite floats at the interface of mercury and water contained in a beaker as shown in the figure. If the densities of granite, water, and mercury are \( \rho \), \( \rho_1 \), and \( \rho_2 \) respectively, the ratio of the volume of granite in water to the volume of granite in mercury is:
A piece of granite floats at the interface of mercury and water
The equation of a stationary wave along a stretched string is given by \[ y = 5 \sin \left( \frac{\pi x}{3} \right) \cos (40 \pi t) \] Additional Information Here, \(x\) and \(y\) are in cm and \(t\) in seconds. The separation between two adjacent nodes is:
Temperature of a body \( \theta \) is slightly more than the temperature of the surrounding \( \theta_s \). Its rate of cooling (R) versus temperature of the body (\( \theta \)) is plotted. Its shape would be: