Recent questions in JEEMAIN PAST PAPERS

Electromagnetic waves are transverse in nature is evident by :

asked Dec 11, 2018 by pady_1

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At absolute zero, Si acts as :

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Heat given to a body which raises its temperature by $1^{\circ}C$ is :

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If a current is passed through a spring then the spring will :

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Two identical particle move towards each other with velocity $ 2v$ and $v$ respectively. The velocity of centre of mass is :

asked Dec 11, 2018 by pady_1

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Wavelength of light used in optical instrument are $\lambda_1 = 4000 \mathring{A}$ and $\lambda_2 = 5000 \mathring{A}$, then ratio of their respective resolving powers (corresponding to $\lambda_1$ and $\lambda_2$) is :

asked Dec 11, 2018 by pady_1

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If in the circuit, power dissipation is 150 W, then $R$ is :

asked Dec 11, 2018 by pady_1

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A charged particle $q$ is placed at the centre $O$ of cube of length $L \;(ABCDEFGH)$. Another same charge $q$ is placed at a distance $L$ from $O$. Then the electric flux through $ABCD$ is :

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If a spring has time period T, and is cut into $n$equal parts, then the time period of each part will be :

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Energy required to move a body of mass $m$ from an orbit of radius $2R$ and $3R$ is :

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If an electron and proton having same momenta enter perpendicularly to a magnetic field, then :

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On moving a charge of 20 C by 2 cm, 2J of work is done, then the potential difference between the points is :

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A wave $y =a \sin (wt-kx)$ on a string meets with another wave producing a node at $x=0$. Then the equation of the unknown wave is :

asked Dec 11, 2018 by pady_1

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A tuning fork arrangement (pair) produces 4 beats/s with one fork of frequency 288 cps. A little wax is placed on the unknown fork and it then produces 2 beats/s. The frequency of the unknown fork is :

asked Dec 11, 2018 by pady_1

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Tube A has both ends open while tube B has one end closed, otherwise they are identical. The raio of fundamental frequency of tubes A and B is :

asked Dec 11, 2018 by pady_1

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If 13.6 eV energy is required to ionize the hydrogen atom, then the energy required to remove an electrons from $n=2$ is :

asked Dec 11, 2018 by pady_1

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A wire when connected to 220 V mains supply has power dissipation $P_1$. Now the wire is cut into two equal piece which are connected in parallel to the same supply. Power dissipation in this case is $P_2$. Then $P_2 : P_1$ is :

asked Dec 11, 2018 by pady_1

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If two mirrors are kept at $ 60^{\circ}$ to each other, then the number of images formed by them is :

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If in a circular coil $A$ of radius $R$, current $i$ is flowing and in another coil $B$ of radius $2R$ a current $2i$ is flowing, then the ratio of the magnetic fields, $B_A$ and $B_B$ produced by them will be :

asked Dec 11, 2018 by pady_1

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If an ammeter is to be used in place of a voltmeter, then we must connect with the ammeter a :

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If suddenly the gravitational force of attraction between earth and a satellite revolving around it becomes zero, then the satellite will :

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If a body loses hald of its velocity on penetrating 3 cm in a wooden block, then how much will it penetrate more before coming to rest ?

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From a building two balls A and B are thrown such that A is thrown upwards and B downwards (both vertically). If $\nu_A$ and $\nu_B$ are their respective velocities on reaching the ground, then :

asked Dec 11, 2018 by pady_1

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A ball whose kinetic energy is E, is projected at an angle of $45^{\circ}$ to the horizontal. The kinetic energy of the ball at the highest point of its flight will be:

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The inductance between A and D is :

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A body travels a distance $s$ in $t$ seconds. It starts from rest and ends at rest. In the first part of the journey, it moves with constant acceleration $f$ and in the second part with constant retardation $r$. The value of $t$ is given by:

asked Dec 11, 2018 by pady_1

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Two stones are projected from the top of a cliff $h$ metres high, with the same speed $u$ so as to hit the ground at the same spot. If one of the stones is projected horizontally and the other is projected at an angle $\theta$ to the horizontal, then $\tan \theta$ equals :

asked Dec 11, 2018 by pady_1

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Two particles start simultaneously from the same point and move along two straight lines, one with uniform velocity $\overrightarrow{u}$ and the other from rest with uniform acceleration $\overrightarrow{f}$. Let $\alpha$ be the angle between their directions of motion. The relative velocity of the second particle w.r.t. the first is least after a time :

asked Dec 11, 2018 by pady_1

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A couple is of momen $\overrightarrow{G}$ and the force forming the couple is $\overrightarrow{P}$. If $\overrightarrow{P}$ is turned through a right angle, the moment of the couple thus formed is $\overrightarrow{H}$. If instead, the forcce $\overrightarrow{P}$ is turned through an angle $\alpha$, then the moment of couple becomes :

asked Dec 11, 2018 by pady_1

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Let $R_1$ and $R_2$ respectively be the maximum ranges up and down an inclined plane and $R$ be the maximum range on the horizontal plane. Then $R_1, \;R, \; R_2$ are in :

asked Dec 11, 2018 by pady_1

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The resultant of forces $\overrightarrow{P}$ and $\overrightarrow{Q}$ is $\overrightarrow{R}$. If $\overrightarrow{Q}$ is doubled, then $\overrightarrow{R}$ is doubled. If the direction of $\overrightarrow{Q}$ is reversed, then $\overrightarrow{R} $ is again doubled, then $p^2 : Q^2 : R^2$ is :

asked Dec 11, 2018 by pady_1

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The mean and variance of a random variable $X$ having a binomial distribution are 4 and 2 respectively, then $P(X=1)$ is :

asked Dec 11, 2018 by pady_1

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Events A, B, C are mutually exclusive events such that $P(A) = \frac{3x +1}{3}, \; P(B) = \frac{1-x}{4} $ and $P(C) = \frac{1-2x}{2}$. The set of possible values of $x$ are in the interval :

asked Dec 11, 2018 by pady_1

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Five horses are in a race. Mr. A selects two of the horses at random and bets on them. The probabiliy that Mr. A selected the winning horse, is :

asked Dec 11, 2018 by pady_1

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In an experiment with 15 observations on $x$, the following results were available $\displaystyle\sum x^2 = 2830, \; \displaystyle\sum x = 170$ One observation that was 20, was found to be wrong and was replaced by the correct value 30. Then the corrected variance is :

asked Dec 11, 2018 by pady_1

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The median of a set of 9 distinct observations is 20.5. If each of the largest 4 observations of the set is increased by 2, then the median of the new set :

asked Dec 11, 2018 by pady_1

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A particle acted on by constant forces $4 \hat{i} + \hat{j} - 3 \hat{k}$ and $3 \hat{i} + \hat{j} - \hat{k}$ is displaced from the point $\hat{i} + 2 \hat{j} + 3 \hat{k}$ to the point $5\hat{i} + 4\hat{j} + \hat{k}$. The total work done by the forces is :

asked Dec 11, 2018 by pady_1

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The vectors $\overrightarrow{AB} = 3\hat{i} + 4 \hat{k}$, and $\overrightarrow{AC} = 5 \hat{i} -2\hat{j} + 4 \hat{k}$ are the sides of a triangle $ABC$. The length of the median through $A$ is :

asked Dec 11, 2018 by pady_1

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Consider points A, B, C and D with position vectors $7 \hat{i} - 4 \hat{j} + 7 \hat{k}, \; \hat{i} - 6 \hat{j} + 10 \hat{k}, \; -\hat{i} - 3 \hat{j} + 4 \hat{k}$ and $5 \hat{i} - \hat{j} + 5 \hat{k}$ respectively. Then ABCD is a :

asked Dec 11, 2018 by pady_1

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If $\overrightarrow{u}, \overrightarrow{v} $ and $\overrightarrow{w}$ are three non-coplanar vectors, then $(\overrightarrow{u} + \overrightarrow{v} - \overrightarrow{w}) . [(\overrightarrow{u} - \overrightarrow{v}) \times (\overrightarrow{v} - \overrightarrow{w} ) ] $ equals :

asked Dec 11, 2018 by pady_1

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$\overrightarrow{a}, \overrightarrow{b}, \overrightarrow{c} $ are three vectors, such that $\overrightarrow{a} + \overrightarrow{b} + \overrightarrow{c} = \overrightarrow{0}, \; |\overrightarrow{a}| = 1, \; |\overrightarrow{b} |= 2, \; |\overrightarrow{c} | = 3$, then $\overrightarrow{a}. \overrightarrow{b} + \overrightarrow{b}.\overrightarrow{c} + \overrightarrow{c}.\overrightarrow{a}$ is equal to :

asked Dec 11, 2018 by pady_1

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Two systems of rectangular axes have the same origin. If a plane cuts them at distances $a, \; b,\; c$ and $a',\;b',\;c'$ from the origin, then :

asked Dec 11, 2018 by pady_1

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The shortest distance from the plane $12x +4y +3z = 327$ to the sphere $x^2 + y^2 + z^2 + 4x - 2y - 6z = 155$ is :

asked Dec 11, 2018 by pady_1

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The two lines $x = ay + b, \; z = cy + d$ and $x = a' y + b', \; z = c' y + d'$ will be perpendicular, if and only if :

asked Dec 11, 2018 by pady_1

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The lines $\frac{x-2}{1} = \frac{y-3}{1} = \frac{z-4}{-k}$ and $\frac{x-1}{k} = \frac{y-4}{2} = \frac{z-5}{1}$ are coplanar if :

asked Dec 11, 2018 by pady_1

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The radius of the circle in which the sphere $x^2 + y^2 + z^2 + 2x - 2y - 4z - 19 = 0$ is cut by the plane $x + 2y + 2z + 7 = 0$ is :

asked Dec 11, 2018 by pady_1

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A tetrahedron has vertices at $O(0, 0, 0),\; A(1,2,1),\; B(2,1,3)$ and $C(-1, 1, 2)$. Then the angle between the faces $OAB$ and $ABC$ will be :

asked Dec 11, 2018 by pady_1

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The foci of the ellipse $\frac{x^2}{16} + \frac{y^2}{b^2} = 1$ and the hyperbola $\frac{x^2}{144} - \frac{y^2}{81} = \frac{1}{25}$ coincide. Then the value of $b^2$ is :

asked Dec 11, 2018 by pady_1

1 answer

The normal at the point $(bt_1^2, 2bt_1)$ on a parabola meets the parabola again in the point $(bt_2^2 , 2bt_2)$ then :

asked Dec 11, 2018 by pady_1

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The lines $2x - 3y = 5$ and $3x - 4y =7$ are diameters of a circle having area as $154\; sq. unit$. Then the equation of the circle is :

asked Dec 11, 2018 by pady_1

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