List of top Questions asked in JEE Main

Two identical cells, when connected either in parallel or in series gives same current in an external resistance $5 \Omega$ The internal resistance of each cell will be__ $\Omega$

A source supplies heat to a system at the rate of 1000 W. If the system performs work at a rate of 200 W. The rate at which internal energy of the system increase is

A thin rod having a length of $1 m$ and area of cross-section $3 \times 10^{-6} m ^2$ is suspended vertically from one end. The rod is cooled from $210^{\circ} C$ to $160^{\circ} C$ After cooling, a mass $M$ is attached at the lower end of the rod such that the length of rod again becomes $1m$. Young's modulus and coefficient of linear expansion of the rod are $2 \times 10^{11} N m ^{-2}$ and $2 \times 10^{-5} K ^{-1}$, respectively. The value of $M$ is ____ $kg$. (Take $g =10 \ m s ^{-2}$)

In a medium the speed of light wave decreases to $0.2$ times to its speed in free space The ratio of relative permittivity to the refractive index of the medium is $x: 1$ The value of $x$ is(Given speed of light in free space $=3 \times 10^8 m s ^{-1}$ and for the given medium $\mu =1$)

An inductor of $0.5 mH$, a capacitor of $20 \mu F$ and resistance of $20 \Omega$ are connected in series with a $220 V$ ac source If the current is in phase with the emf, the amplitude of current of the circuit is $\sqrt{x}$ A The value of $x$ is -

Compound A reacts with $NH _4 Cl$ and forms a compound B Compound B reacts with $H _2 O$ and excess of $CO _2$ to form compound $C$ which on passing through or reaction with saturated $NaCl$ solution forms sodium hydrogen carbonate Compound $A , B$ and $C$, are respectively

Let $\overrightarrow{a}=3\^i+\^j −\^k$ and $\overrightarrow{c}=2\^i+3\^j −3\^k$ if $\overrightarrow{b}$ is a vector such that $\overrightarrow{a}=\overrightarrow{b}\times\overrightarrow{c}$ and $|\overrightarrow{b}|=50$ , then $|72|\overrightarrow{b}+\overrightarrow{c}|^2|$| | is equal to _______.

Which of the following statements is incorrect for antibiotics?

If S={ x ∈ R : sin⁻¹$( \frac{x + 1}{ √ x^ 2 + 2 x + 2} ) $−-sin⁻¹$(\frac{x}{√x ^2+1 }) = \frac{π}{ 4} $}
then $∑_{x∈R }(sin( (x^2+x+5)\frac{π}{2})−cos( ( x^2+x+5)π ) ) $is equal to ____.

Kinetic energy of electron, proton and a particle is given as K, 2K and 4K respectively, then which of the following gives the correct order of De-Broglie wavelengths of electron, proton and a particle

The correct order in aqueous medium of basic strength in case of methyl substituted amines is :

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R Assertion (A): Earth has atmosphere and moon doesn’t Reason (R): escape speed on moon is less than that Earth. In the light of the above statements, choose the correct answer from the options given below

A solid sphere of mass $1 \,kg$ rolls without slipping on a plane surface Its kinetic energy is $7 \times 10^{-3} J$. The speed of the centre of mass of the sphere is ___$cm s ^{-1}$.

The correct sequence of reagents for the preparation of Q and R is:

Find area bounded by the curves $y$ = $max\{sin x, cos x\}$ and $x-axis$ between $x = - \pi $and $x = \pi$

A lift of mass $M =500 kg$ is descending with speed of $2 ms ^{-1}$ Its supporting cable begins to slip thus allowing it to fall with a constant acceleration of $2 ms ^{-2}$ The kinetic energy of the lift at the end of fall through to a distance of $6 m$ will be ___ $kJ$

The radius of the $2^{\text {nd }}$ orbit of $Li ^{2+}$ is $x$. The expected radius of the $3^{\text {rd }}$ orbit of $Be ^{3+}$ is

Let m1 and m2 be the slopes of the tangents drawn from the point P(4,1) to the hyperbola H : $\frac{y^2}{25} − \frac{x^2}{16 }$= 1. If Q is the point from which the tangents drawn to H have slopes |m₁| and |m₂| and they make positive intercepts α and β on the x-axis, then $\frac{( P Q ) ^2}{ α β}$ α β is equal to _____.

A cubic solid is made up of two elements $X$ and $Y$ Atoms of $X$ are present on every alternate corner and one at the enter of cube $Y$ is at $\frac{1}{3} td$ of the total faces The empirical formula of the compound is

Let α be the constant term in the binomial expansion of $ (√x−\frac{6}{x^{\frac{3}{2}}} )^n ,n≤15.$ If the sum of the coefficients of the remaining terms in the expansion is 649 and the coefficient of x^-n is λα, then λ is equal to _______.

The variation of the rate of an enzyme catalyzed reaction with substrate concentration is correctly represented by graph

For hydrogen atom, $\lambda_1$ and $\lambda_2$ are the wavelengths corresponding to the transitions 1 and 2 respectively as shown in figure The ratio of $\lambda_1$ and $\lambda_2$ is $\frac{x}{32}$ The value of $x$ is

Find out the oxidation number of the central metal atom of fe(CO)₅ , VO₂⁺, and WO₃. Then calculate the sum of their oxidation state.

The number of seven-digit positive integers formed using the digits 1, 2, 3, and 4 only, and whose sum of the digits is 12, is

Coagulating value of the electrolytes AlCl₃ and NaCl for As₂S₃ are 0.09 and 50.04 respectively. The coagulating power of AlCl₃ is x times the coagulating power of NaCl. The value of x is ______ .