List of top Questions asked in JEE Main

Which technique among the following, is most appropriate in separation of a mixture of $100\, mg$ of $p$-nitrophenol and picric acid ?

The difference in the reaction of phenol with bromine in chloroform and bromine in water medium is due to :

Given below are two statements: 
Statement I: The average momentum of a molecule in a sample of an ideal gas depends on temperature. 
Statement II: The rms speed of oxygen molecules in a gas is $v$ If the temperature is doubled and the oxygen molecules dissociate into oxygen atoms, the rms speed will become $2 v$ In the light of the above statements, choose the correct answer from the options given below:

In the wave equation $y=05 \sin \frac{2 \pi}{\lambda}(400 t-x) m$ the velocity of the wave will be :

Two capacitors, each having capacitance $40 \mu F$ are connected in series The space between one of the capacitors is filled with dielectric material of dielectric constant $K$ such that the equivalence capacitance of the system became $24 \mu F$ The value of $K$ will be :

A wire of resistance $R_1$ is drawn out so that its length is increased by twice of its original length The ratio of new resistance to original resistance is:

Given below are two statements : Statement I : On heating with \(KHSO _4\), glycerol is dehydrated and acrolein is formed 
Statement II : Acrolein has fruity odour and can be used to test glycerol's presence Choose the correct option

The total number of functions, \(f :\{1,2,3,4\} \rightarrow\{1,2,3,4,5,6\}\) such that \(f (1)+ f (2)= f (3)\), is equal to :

A line, with the slope greater than one, passes through the point A (4,3) and intersects the line x-y-2=0 at the point B If the length of the line segment AB is \(\frac{\sqrt{29}}{3},\) then B also lies on the line :

The current sensitivity of a galvanometer can be increased by: 
(A) decreasing the number of turns 
(B) increasing the magnetic field 
(C) decreasing the area of the coil 
(D) decreasing the torsional constant of the spring Choose the most appropriate answer from the options given below:

If \(\alpha, \beta, \gamma, \delta\) are the roots of the equation \(x ^4+ x ^3+ x ^2+ x +1=0\), then \(\alpha^{2021}+\beta^{2021}+\gamma^{2021}+\delta^{2021}\) is equal to

The correct stability order of the following diazonium salt is

Let the locus of the centre \((\alpha, \beta), \) \(\beta>0\), of the circle which touches the circle \(x ^2+( y -1)^2=1\) externally and also touches the x-axis be L Then the area bounded by L and the line y=4 is :

If the sum and the product of mean and variance of a binomial distribution are 24 and 128 respectively, then the probability of one or two successes is :

For \(n \in N\), let \(S _{ n }=\left\{ z \in C :| z -3+2 i |=\frac{ n }{4}\right\}\) and \(T_n=\left\{z \in C:|z-2+3 i|=\frac{1}{n}\right\}\) Then the number of elements in the set \(\left\{ n \in N : S _{ n } \cap T _{ n }=\phi\right\}\) is :

Stearic acid and polyethylene glycol react to form which one of the following soaps/detergents ?

As shown in the figure, a metallic rod of linear density \(0.45\ kg m^{-1}\) is lying horizontally on a smooth incline plane which makes an angle of 45° with the horizontal. The minimum current flowing in the rod required to keep it stationary, when \(0.15 T\) magnetic field is acting on it in the vertical upward direction, will be: {Use \(g = 10 m/s^2\)}

The equation of current in a purely inductive circuit is $5 \sin \left(49 \pi t -30^{\circ}\right)$ If the inductance is $30\, mH$ then the equation for the voltage across the inductor, will be: $\left\{\text { Let } \pi=\frac{22}{7}\right\}$

Three masses \(M =100 \,kg , m _1=10\, kg\) and \(m _2=20 \,kg\) are arranged in a system as shown in figure All the surfaces are frictionless and strings are inextensible and weightless The pulleys are also weightless and frictionless A force \(F\) is applied on the system so that the mass \(m _2\) moves upward with an acceleration of \(2\, ms ^{-2}\) The value of \(F\) is : (Take \(\text g=10\;ms^-2\))

\(B_X\) and \(B_Y\) are the magnetic field at the centre of two coils of two coils \(X\) and \(Y\) respectively, each carrying equal current If coil \(X\) has \(200\) turns and \(20\, cm\) radius and coil \(Y\) has \(400\) turns and \(20 \,cm\) radius, the ratio of \(B_X\) and \(B_Y\) is

As shown in the figure, after passing through the medium 1. The speed of light v₂ in medium 2 will be: (Given \(c = 3 \times 10^8 ms^{-1}\))

\(7\) mole of certain monoatomic ideal gas undergoes a temperature increase of \(40\, K\) at constant pressure The increase in the internal energy of the gas in this process is (Given \(R =83\, JK ^{-1}\, mol ^{-1}\))

In normal adjustment, for a refracting telescope, the distance between objective and eye piece is $30\,cm$ The focal length of the objective, when the angular magnification of the telescope is 2, will be: