Recent questions and answers in JEEMAIN PAST PAPERS

Several blocks of magnesium are fixed to the bottom of a ship to :

answered Aug 29, 2021 by connoisseur.2017

1 answer

Three charges $-q_1,\;+q_2$ and $-q_3$ are placed as shown in the figure. The x-component of the force on $-q_1$ is proportional to :

answered Jun 21, 2021 by lipsasahoo941

1 answer

Two points P and Q are maintained at the potentials of 10V and -4V respectively. The work done in moving 100 electrons from P to Q is

answered Jun 6, 2021 by abinashkumarnath6

1 answer

If the electric flux entering and leaving an enclosed surface respectively is $\phi_1$ and $\phi_2$, the electric charge inside the surface will be :

answered Feb 25, 2021 by girishbiradar259

1 answer

If two towers of height $h_1$ and $h_2$ subtend angles $60^{\circ} $ and $30^{\circ}$ respectively at the mid point of the line joining their feet, then $h_1:h_2$ is equal to:

answered Feb 22, 2021 by snehabijusmitha

1 answer

The trans-alkenes are formed by the reduction of alkynes with ?

answered Feb 2, 2021 by abdulrahimshafiuyusuf

1 answer

A mixture contains four solid organic compounds A, B, C, D. On heating only C changes from solid to vapours state. C can be separated from the rest in the mixture by :

answered Nov 9, 2020 by amrutaraghushe007

1 answer

A simple pendulum hanging freely and at rest is vertical because in that position :

answered Sep 19, 2020 by hiteshrajput2201

1 answer

If $\lambda x^2 + 6xy + 9y^2 +4x + 12y+3=0$ represents a pair of straight lines, then $\lambda$ is equal to :

answered Aug 14, 2020 by shadowdragon123345

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Which of the following converts acetone to acetone oxime ?

answered Jul 26, 2020 by akashhkumar5

1 answer

The solvent used in the preparation of Grignard reagent is :

answered Jul 20, 2020 by kphasnashirin

1 answer

If $a, h, b$ are in A.P., then the triangular area formed by the pair of lines $ax^2 + 2hxy + by^2=0$ and the line $x-y=-2$ (in square units) is :

answered Jul 20, 2020 by sarmagoruganthu

1 answer

A solid organic compound $X$ on heating is directly converted into the vapour phase which on cooling solidifies. The best method for purifying $X$ is :

answered Jul 20, 2020 by yathapusaikumarreddy2003

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The line $4x +6y+9=0$, touches the parabola $y^2 =4x$ at the point :

answered Jul 6, 2020 by vibhaas93

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Tinstone is contaminated with Wolframite. Which one of the following methods can be employed to dress the tinstone ore ?

answered Jun 20, 2020 by nalamasuabhinay

1 answer

In a compound microscope cross wires are fixed at the point :

answered Jun 10, 2020 by kelvinayagan

1 answer

If the acute angle between the curves $xy=2$ and $y^2 = 4x$ is $\theta$, then $\tan \theta$ is equal to :

answered Jun 6, 2020 by bmreddy497

1 answer

A ball A moving with a speed of $99\;ms^{-1}$ collides directly with another identical ball B moving with a speed $v$ in the opposite direction, A comes to rest after the collision. If the coefficients of restitution is 0.8, the speed of B before collision, is :

answered Jun 2, 2020 by bheemsenkulkarni181

1 answer

In a $\Delta ABC$, $\tan \frac{A}{2} = \frac{5}{6}, \; \tan \frac{C}{2} = \frac{2}{5}$, then :

answered Jun 2, 2020 by tharunkona111

1 answer

The equation of the directrix to the parabola $y^2 -2x - 6y -5 = 0$ is

answered May 23, 2020 by shinuanudeep

1 answer

Which of the following reactions does not involve change in the oxidation state of the metal ?

answered May 18, 2020 by fasakdioboy

1 answer

If the lines $\frac{x-1}{2} = \frac{y+1}{3} = \frac{z-1}{4}$ and $ \frac{x-3}{1} = \frac{y-k}{2} = \frac{z}{1}$ intersect, then $k$ is equal to

answered May 15, 2020 by priyanka.clay6

1 answer

Let $x_1, x_2, ....., x_n$ be $n$ observations, and let $\overline{x}$ be their arithematic mean and $\sigma^2$ be their variance. Statement 1 : Variance of $2x_1, 2x_2, ....,2x_n$ is $4 \sigma^2$ Statement 2 : Arithmetic mean of $2x, 2x_2, .... , 2x_n$ is $4 \overline{x}$.

answered May 15, 2020 by priyanka.clay6

1 answer

If the line $2x + y = k$ passes through the point which divides the line segment joining the points (1, 1) and (2, 4) in the ratio $ 3 : 2$, then $k$ equals

answered May 15, 2020 by priyanka.clay6

1 answer

In a $\Delta PQR$, if $ 3 \sin P + 4 \cos Q = 6 $ and $4 \sin Q + 3 \cos P = 1$, then the angle R is equal to

answered May 15, 2020 by priyanka.clay6

1 answer

Acetyl bromide reacts with excess of $CH_3MgI$ followed by treatment with a saturated solution of $NH_4Cl$ given

answered May 13, 2020 by meena.clay6

1 answer

On mixing ethyl acetate with aqueous sodium chloride, the composition of the resultant solution is

answered May 13, 2020 by meena.clay6

2 answers

The compound formed on heating chlorobenzene with chloral in the presence concentrated sulphuric acid is

answered May 13, 2020 by meena.clay6

2 answers

Which base is present in RNA but not in DNA ?

answered May 13, 2020 by meena.clay6

2 answers