List of top Questions asked in JEE Main

Which of the following statement is correct ?

In two different experiments, an object of mass $5\, kg$ moving with a speed of $25 \,ms ^{-1}$ hits two different walls and comes to rest within
(i) 3 second,
(ii) 5 seconds, respectively.
Choose the correct option out of the following :

The compound(s) that is(are) removed as slag during the extraction of copper is :

$CaO$
$FeO$
$Al _2 O _3$
$ZnO$
$NiO$
Choose the correct answer from the options given below :

The number of $\theta \in(0,4 \pi) $for which the system of linear equations $3(\sin 3 \theta) x-y+z=2$ $3(\cos 2 \theta) x+4 y+3 z=3$ $6 x+7 y+7 z=9$ has no solution is :

A balloon has mass of 10 g in air The air escapes from the balloon at a uniform rate with velocity 4.5 cm/s If the balloon shrinks in 5 s completely Then, the average force acting on that balloon will be (in dyne)

Two projectile thrown at $30^{\circ}$ and $45^{\circ}$ with the horizontal respectively, reach the maximum height in same time The ratio of their initial velocities is

If $\displaystyle\lim _{n \rightarrow \infty}\left(\sqrt{n^2-n-1}+n \alpha+\beta\right)=0 $ then $8(\alpha+\beta)$ is equal to :

Choose the correct order of density of the alkali metals :

The interhalogen compound formed from the reaction of bromine with excess of fluorine is a :

If the absolute maximum value of the function $f(x)=\left(x^2-2 x+7\right) e^{\left(4 x^3-12 x^2-180 x+31\right)}$ in the interval [-3,0] is $f(\alpha)$, then:

The photochemical smog does not generally contain :

A screw gauge of pitch $05 \,mm$ is used to measure the diameter of uniform wire of length $68 \,cm$, the main scale reading is $15\, mm$ and circular scale reading is $7$. The calculated curved surface area of wire to appropriate significant figures is :[Screw gauge has $50$ divisions on the circular scale]

If the radius of earth shrinks by $2 \%$ while its mass remains same The acceleration due to gravity on the earth's surface will approximately :

Refining using liquation method is the most suitable for metals with :

Which of the following can be used to prevent the decomposition of $H _2 O _2$ ?

The force required to stretch a wire of cross-section $1 cm ^2$ to double its length will be: (Given Yong's modulus of the wire $=2 \times 10^{11} N / m ^2$ )

Reaction of $BeCl _2$ with $LiAlH _4$ gives: Choose the correct answer from options given below :

$AlCl _3$
$BeH _2$
$LiH$
$LiCl$
$BeAlH _4$

The area of the region given by $A =\left\{( x , y ): x ^2 \leq y \leq \min \{ x +2,4-3 x \}\right\}$ is :

A Carnot engine has efficiency of $50 \%$ .If the temperature of sink is reduced by $40^{\circ} C$, its efficiency increases by $30 \%$ .The temperature of the source will be :

Borazine, also known as inorganic benzene, can be prepared by the reaction of 3-equivalents of "$X$" with 6-equivalents of "Y". "X" and "Y", respectively are :

For any real number x, let [ x ] denote the largest integer less than equal to x Let f be a real valued function defined on the interval [-10,10] by $f(x)=\begin{cases} x-[x], & \text { if }(x) \text { is odd } \\ 1+[x]-x & \text { if }(x) \text { is even }\end{cases}$Then the value of$ \frac{\pi^2}{10} \int\limits_{-10}^{10} f(x) \cos \pi x d x$ is :

The slope of the tangent to a curve C : y=y(x) at any point [x, y) on it is $\frac{2 e ^{2 x }-6 e ^{- x }+9}{2+9 e ^{-2 x }}$ If C passes through the points $\left(0, \frac{1}{2}+\frac{\pi}{2 \sqrt{2}}\right) $and $\left(\alpha, \frac{1}{2} e ^{2 \alpha}\right)$$ then $e ^\alpha$ is equal to :

Which of the given reactions is not an example of disproportionation reaction?

The dark purple colour of $KMnO _4$ disappears in the titration with oxalic acid in acidic medium. The overall change in the oxidation number of manganese in the reaction is :

$\dot{ C } l + CH _4 \rightarrow A + B$. $A$ and $B$ in the above atmospheric reaction step are