List of top Questions asked in WBJEE

Pick the correct statement:
A straight wire is placed in a magnetic field that varies with distance $x$ from origin as $B = B_0 (2 - \frac{x}{n}) \hat{k}$. The ends of the wire are at $(a, 0)$ and $(2n, 0)$ and it carries a current $I$. If the force on the wire is $F = 1 B_0 \left(\frac{k a}{2}\right) \hat{j}$, then the value of $k$ is
If a string suspended from the ceiling is given a downward force $F_1$, its length becomes $L_1$. Its length is $L_2$ if the downward force is $F_2$. What is its actual length?
A golf ball of mass $50$ gm placed on a tee is struck by a golf club. The speed of the ball as it leaves the tee is $100$ m/s, and the time of contact on the ball is $0.02$ s. If the force decreases to zero linearly with time, then the force at the beginning of the contact is
Hybridisation of the negative carbons in (1) and (2) are:
Hybridisation of the negative carbons
A sample of MgCO3 is dissolved in dilute HCl and the solution is neutralized with ammonia and buffered with NH4Cl / NH4OH. Disodium hydrogen phosphate reagent is added to the resulting solution. A white precipitate is formed. What is the formula of the precipitate?
The correct order of acidity of the following hydra acids is:
Two wires $A$ and $B$ of the same length are made of the same material. The Load ($F$) vs. elongation ($x$) graph for these two wires is shown in the figure. Then which of the following statement(s) is/are true?
Two wires A and B of the same length are made of same material Load
Find the equivalent capacitance between $A$ and $B$ of the following arrangement:
equivalent capacitance
The correct statement(s) about B2H6 is/are:
How many monobrominated product(s) (including stereoisomers) would form in the free radical bromination of n-butane?
What is the correct order of acidity of salicylic acid, 4-hydroxybenzoic acid, and 2,6-dihydroxybenzoic acid?
The enol form in which ethyl-3-oxobutanoate exists is
The correct order of relative stability of the given conformers of n-butane is
order of relative stability
The major product of the following reaction is $F_3C \rightarrow CH = CH_2 + HBr$
The correct order of relative stability for the given free radical is:
Which of the following is radioactive?
The product of the following hydrogenation reaction is:
$1$ mL of water has $25$ drops. Let $N_A$ be the Avogadro number. What is the number of molecules present in $1$ drop of water? (Density of water = $1$ g/mL)
The product of the following reaction is:
Which of the following would produce enantiomeric products when reacted with methyl magnesium iodide?
Two infinite line charges parallel to each other are moving with a constant velocity $v$ in the same direction as shown in the figure. The separation between two line charges is $d$. The magnetic attraction balances the electric repulsion when, [e = speed of light in free space]
Two infinite line charges parallel to each other are moving with
A Zener diode having a breakdown voltage $V_z = 6$ V is used in a voltage regulator circuit as shown in the figure. The minimum current required to pass through the Zener to act as a voltage regulator is $10$ mA and the maximum allowed current through the Zener is $40$ mA. The maximum value of $R_\delta$ for Zener to act as a voltage regulator is
A Zener diode having a breakdown voltage
The correct relationship between molecule I and II is:
correct relationship between molecule I and II
The average speed of $H_2$ at $T_1$ K is equal to that of $O_2$ at $T_2$ K. The ratio $T_1:T_2$ is