Recent questions and answers in JEEMAIN-2017

The following statement $(p \to q)\to [(\approx p \to q)\to q]$ is :

answered Jun 3, 2021 by ranjani.hogwarts

1 answer

For three events A, B and C, P(Exactly one of A or B occurs) =P(Exactly one of B or C occurs) =P(Exactly one of C or A occurs)= $\large\frac{1}{4}$ and P(All the three events occur simultaneously)= $\large\frac{1}{16}$ .Then the probability that at least one of the events occurs, is :

answered Apr 5, 2019 by annapurnachoudhary1415

1 answer

A time dependent force $F=6t$ acts on a particle of mass $1\;kg$ . If the particle starts from rest, the work done by the force during the first 1 sec. will be :

answered Jan 13, 2019 by archanaanu83

1 answer

The radius of a circle, having minimum area, which touches the curve $y=4−x^2$ and the lines, $y=|x|$ is :

answered Jan 8, 2019 by sukhmandeepsandhu21

1 answer

A water sample has ppm level concentration of following anions $F^{-}= 10 ; SO_4^{2-}= 100 ; NO_3^{-}= 50$ The anion/anions that make/makes the water sample unsuitable for drinking is/are :

answered Dec 25, 2018 by kanchanhp12

1 answer

Magnetic field in a plane electromagnetic wave is given by $\overrightarrow{B} =B_0 \sin (kx+ \omega t) \hat j T$ Expression for corresponding electric field will be : Where c is speed of light.

answered Dec 8, 2018 by mstbsdmgv

1 answer

Magnetic field in a plane electromagnetic wave is given by $\overrightarrow{B}= B_0 \sin (kx + \omega t) \hat{j} T$ Expression for corresponding electric field will be :
Where c is speed of light.

answered Nov 9, 2018 by vaibhavishastri01

1 answer

A diverging lens with magnitude of focal length 25 cm is placed at a distance of 15 cm from a converging lens of magnitude of focal length 20 cm. A beam of parallel light falls on the diverging lens. The final image formed is :

answered Sep 28, 2018 by smitdama786

1 answer

A metal crystallises in a face centred cubic structure. If the edge length of its unit cell is ‘a’, the closest approach between two atoms in metallic crystal will be :

answered Sep 24, 2018 by ahujasapna99

1 answer

Both lithium and magnesium display several similar properties due to the diagonal relationship; however, the one which is incorrect, is :

answered May 1, 2018 by sharmaaparna1

1 answer

In amplitude modulation, sinusoidal carrier frequency used is denoted by $\omega_c$ and the signal frequency is denoted by $\omega _m$ The bandwidth $(\Delta \omega _m)$ of the signal is such that $\Delta \omega_m << \omega_c$ . Which of the following frequencies is not contained in the modulated wave ?

answered Apr 25, 2018 by pandeyhimanshu259

1 answer

A particle A of mass m and initial velocity $v$ collides with a particle $B$ of mass $\large\frac{m}{2}$ which is at rest. The collision is head on, and elastic. The ratio of the de-Broglie wavelengths $\lambda_A$ to $\lambda_B$ after the collision is :

answered Apr 15, 2018 by mishramanish1601ak

1 answer

$_p K_a$ of a weak acid (HA) and $_pK_b$ of a weak base $(BOH)$ are 3.2 and 3.4, respectively.The pH of their salt (AB) solution is :

answered Mar 26, 2018 by dkpatel24121995

1 answer

If $A= \begin{bmatrix} 2 & -3 \\ -4 & 1 \end{bmatrix}$ then adj $(3A^2+12A)$ is equal to :

answered Jan 31, 2018 by mahawarravi036

2 answers

When a current of $5 \;mA$ is passed through a galvanometer having a coil of resistance $15 \Omega$ , it shows full scale deflection. The value of the resistance to be put in series with the galvanometer to convert it into a voltmeter of range $0−10\; V$ is :

answered Jan 20, 2018 by mahawarravi036

2 answers

Let the refractive index of a denser medium with respect to a rarer medium be $n_{12}$ and its critical angle be $\theta C$ . At an angle of incidence A when light is travelling from denser medium to rarer medium, a part of the light is reflected and the rest is refracted and the angle between reflected and refracted rays is 908. Angle A is given by :

asked Aug 9, 2017 by meena.p

0 answers

Let a vertical tower AB have its end A on the level ground. Let C be the mid-point of AB and P be a point on the ground such that $AP=2AB$ . If $\angle BPC=\beta$ , then $\tan \beta$ is equal to :

asked Aug 4, 2017 by meena.p

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If $5(tan^2 x−cos^2 x)=2cos 2x+9$ , then the value of $\cos 4x$ is :

asked Aug 4, 2017 by meena.p

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If two different numbers are taken from the set {0, 1, 2, 3, ......, 10}; then the probability that their sum as well as absolute difference are both multiple of 4, is :

asked Aug 4, 2017 by meena.p

0 answers

A box contains 15 green and 10 yellow balls. If 10 balls are randomly drawn, one-by-one, with replacement, then the variance of the number of green balls drawn is :

asked Aug 4, 2017 by meena.p

0 answers

Let $\overrightarrow{a}= 2\hat i +\hat j -2 \hat k$ and $\overrightarrow{b}= \hat i +\hat j$ . Let $\overrightarrow{c}$ be a vector such that $\bigg|\overrightarrow{c}-\overrightarrow{a} \bigg|= 3,\bigg|(\overrightarrow{a} \times \overrightarrow{b} ) \times \overrightarrow{c} \bigg|=3$ and the angle between $\overrightarrow{c}$ and $\overrightarrow{a} \times \overrightarrow{b}$ be $30^{\circ}$ . Then $\overrightarrow{a}.\overrightarrow{c}$ is equal to :

asked Aug 4, 2017 by meena.p

0 answers

If the image of the point P(1, −2, 3) in the plane, $2x+3y−4z+22=0$ measured parallel to the line, $\large\frac{x}{1}=\frac{y}{4}=\frac{z}{5}$ is Q, then PQ is equal to :

asked Aug 4, 2017 by meena.p

0 answers

The distance of the point (1, 3, −7) from the plane passing through the point $(1, −1, −1),$ having normal perpendicular to both the lines $\large\frac{x-1}{1}=\frac{y+2}{-2}=\frac{z-4}{3}$ and $\large\frac{x-2}{2}=\frac{y-1}{-1}=\frac{z+7}{-1}$ , is:

asked Aug 4, 2017 by meena.p

0 answers

A hyperbola passes through the point $P( \sqrt {2} , \sqrt{3} )$ and has foci at $(\pm 2, 0)$ . Then the tangent to this hyperbola at P also passes through the point :

asked Aug 4, 2017 by meena.p

0 answers

The eccentricity of an ellipse whose centre is at the origin is $\large\frac{1}{2}$ . If one of its directrices is $x=−4,$ then the equation of the normal to it at $\bigg(1,\large\frac{3}{2}\bigg)$ is :

asked Aug 4, 2017 by meena.p

0 answers

Let k be an integer such that the triangle with vertices (k, −3k), (5, k) and (−k, 2) has area 28 sq. units. Then the orthocentre of this triangle is at the point:

asked Aug 4, 2017 by meena.p

0 answers

If $(2+\sin x) \large\frac{dy}{dx}$ $+(y+1) \cos x=0$ and $y(0)=1$ , then $y \bigg(\large\frac{\pi}{2} \bigg)$ is equal to :

asked Aug 4, 2017 by meena.p

0 answers

The area (in sq. units) of the region $\{(x, y) : x/0, x+y≤3, x2≤4y \;and\; y≤1+ x \}$ is :

asked Aug 4, 2017 by meena.p

0 answers

The integral $\int \limits_{\pi/4}^{3 \pi/4} \large\frac{dx}{1+\cos x}$ is equal to :

asked Aug 4, 2017 by meena.p

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Let $I_n= \int \tan^n x dx , (n > 1)$ If $I_4+I_6=a \tan^5 x+bx^5+C$ where C is a constant of integration, then the ordered pair (a, b) is equal to :

asked Aug 3, 2017 by meena.p

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Twenty meters of wire is available for fencing off a flower-bed in the form of a circular sector. Then the maximum area (in sq. m) of the flower-bed, is :

asked Aug 3, 2017 by meena.p

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The normal to the curve $y(x−2)(x−3)=x+6$ at the point where the curve intersects the y-axis passes through the point :

asked Aug 3, 2017 by meena.p

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If for $x \in \bigg( 0, \large\frac{1}{4} \bigg)$ the derivative of $\tan ^{-1} \bigg( \large\frac{6x \sqrt x}{1-9x^3}\bigg)$ is $\sqrt x .g(x)$ then $g(x)$ equals

asked Aug 3, 2017 by meena.p

0 answers

$\lim_{x \to \large\frac{\pi}{2}} \Large\frac{\cot x - \cos x}{(\pi -2x)^3}$ equals :

asked Aug 1, 2017 by meena.p

0 answers

Let $a, b, c \in R$ . If $f(x)=ax^2 +bx+c$ is such that $a+b+c=3$ and $f (x+y)=f(x)+f(y)+xy, ∀ x, y \in R$ , then $\sum\limits_{n=1}^{90} f(n)$ is equal to :

asked Aug 1, 2017 by meena.p

0 answers

For any three positive real numbers a, b and c, $9(25a^2+b^2) +25(c^2−3ac)=15b(3a+c)$ . Then

asked Aug 1, 2017 by meena.p

0 answers

The value of $(^{21}C_1 - ^{10} C_1) +(^{21} C_2 -^{10}C_2) +(^{21}C_3 - ^{10} C_3) +(^{21}C_4 - ^{10} C_4) +.....+ (^{21}C_{10} - ^{10} C_{10})$ is :

asked Aug 1, 2017 by meena.p

0 answers

A man X has 7 friends, 4 of them are ladies and 3 are men. His wife Y also has 7 friends, 3 of them are ladies and 4 are men.Assume X and Y have no common friends.Then the total number of ways in which X and Y together can throw a party inviting 3 ladies and 3 men, so that 3 friends of each of X and Y are in this party, is :

asked Jul 31, 2017 by meena.p

0 answers

If S is the set of distinct values of ‘b’ for which the following system of linear equations $x+y+z=1 \\ x+ay+z=1 \\ ax+by+z=0$ has no solution, then S is :

asked Jul 31, 2017 by meena.p

0 answers

Let $\omega$ be a complex number such that $2 \omega +1=z$ where $z= \sqrt{-3}$ . $\begin{bmatrix} 1 & 1 & 1 \\ 1 & -\omega^2-1 & \omega^2 \\ 1 & \omega^2 & \omega^7 \end{bmatrix}=3k$ then k is equal to :

asked Jul 31, 2017 by meena.p

0 answers

If, for a positive integer n, the quadratic equation, $x(x+1)+(x+1)(x+2)+....+(x+ \bar{n- 1}) (x+n)=10n$ has two consecutive integral solutions, then n is equal to :

asked Jul 31, 2017 by meena.p

0 answers

The function $f: R \to \bigg[ -\large\frac{1}{2} ,\frac{1}{2} \bigg]$ defined as $f(x) = \large\frac{x}{1+x^2}$ is

asked Jul 31, 2017 by meena.p

0 answers

The major product obtained in the following reaction is :

asked Jul 31, 2017 by meena.p

0 answers

The correct sequence of reagents for the following conversion will be :

asked Jul 31, 2017 by meena.p

0 answers

3-Methyl-pent-2-ene on reaction with HBr in presence of peroxide forms an addition product. The number of possible stereoisomers for the product is :

asked Jul 31, 2017 by meena.p

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Which of the following compounds will behave as a reducing sugar in an aqueous $KOH$ solution ?

asked Jul 31, 2017 by meena.p

0 answers

The major product obtained in the following reaction is :

asked Jul 31, 2017 by meena.p

0 answers

The increasing order of the reactivity of the following halides for the $S_N1$ reaction is :

asked Jul 31, 2017 by meena.p

0 answers

Which of the following molecules is least resonance stabilized ?

asked Jul 31, 2017 by meena.p

0 answers

The formation of which of the following polymers involves hydrolysis reaction ?

asked Jul 31, 2017 by meena.p

0 answers

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