Recent questions in JEEMAIN and NEET

Four bodies $P, \; Q, \; R$ and $S$ are projected with equal velocities having angles of projection $15^{\circ}, \; 30^{\circ}, \; 45^{\circ}$ and $60^{\circ}$ with the horizontal respectively. The body having shortest range is :

asked Dec 19, 2018 by pady_1

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A body is thrown horizontally from the top of a tower of 5 m height. It touches the ground at a distance of 10 m from the foot of the tower. The initial velocity of the body is:

asked Dec 19, 2018 by pady_1

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A body is thrown vertically upwards with an initial velocity $u$ reaches maximum height in $6\;sec$ . The ratio of distance travelled by the body in the first and seventh second is :

asked Dec 19, 2018 by pady_1

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The displacement $r$ of a charge $Q$ in an electric field $\overrightarrow{E} = c_1 \hat{i} + c_2 \hat{j} + c_3 \hat{k}$ is $\overrightarrow{r} = a \hat{i} + b \hat{j}$ . The work done is :

asked Dec 19, 2018 by pady_1

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If pressure $P$ , velocity $v$ and time $T$ are taken as fundamental physical quantities the dimensional formula of the force is :

asked Dec 19, 2018 by pady_1

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The fundamental physical quantities that have same dimensions in the dimensional formula of torque and angular momentum are :

asked Dec 19, 2018 by pady_1

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Consider the following statements A and B and identify the correct choice of the given answers : (A) The width of the depletion layer in a $p-n$ junction diode increases in forward bias. (B) In a intrinsic semiconductor the fermi energy level in exactly in the middle of the forbidden energy gap.

asked Dec 19, 2018 by pady_1

0 answers

To generate power of $3.2\; MW$ , the number of fissions $U^{235}$ per minute is : (Energy released per fission = $200\; MeV, \; 1eV =1.6 \times 10^{-19} J$ )

asked Dec 19, 2018 by pady_1

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In Bohr model of hydrogen atom, the ratio of period of revolutionn of an electron in $n=2$ and $n=1$ orbit is :

asked Dec 19, 2018 by pady_1

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The ratio of the longest and shortest wave-lengths in Bracket series of hydrogen spectra is :

asked Dec 19, 2018 by pady_1

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The energy of an X-ray photon of wavelength $1.65 \mathring{A}$ is : ( $h = 6.6 \times 10^{-34} Js, \; c = 3 \times 10^8 ms^{-1}, \; 1eV = 1.6 \times 10^{-19}J$ )

asked Dec 19, 2018 by pady_1

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When a metal surface is illuminated by a light of wavelength $400\;nm$ and $250\; nm$ . The maximum velocities of the photo electrons ejected are $v$ and $2v$ respectively. The work function of the metal is : (h = Planck's constant, c = velocity of light in air )

asked Dec 19, 2018 by pady_1

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The $X$ -ray wavelength of $L_a$ line of platinum $(Z = 78)$ is $1.30 \mathring{A}$ . The $X$ -ray wavelenght of $L_a$ line of molybdenum $(Z =42)$ is :

asked Dec 19, 2018 by pady_1

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Two wires of equal diameters of resistivities $\rho_1$ and $\rho_2$ and lengths $x_1$ and $x_2$ respectively are joined in series. The equivalent resistivity of the combination is :

asked Dec 19, 2018 by pady_1

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Two electric charges $12 \mu C$ and $-6 \mu C$ are placed $20\;cm$ apart in air, there will be a point $P$ at which electric potential is zero on the line joining these two charges and out side excluding the region between them. The distance of $P$ from $-6 \mu C$ charge is :

asked Dec 19, 2018 by pady_1

0 answers

An ammeter and a voltmeter of resistance $R$ are connected in series to an electric cell of negligible internal resistance. Their readings are A and V respectively. If another resistance $R$ is connected in parallel with voltmeter :

asked Dec 19, 2018 by pady_1

0 answers

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

asked Dec 19, 2018 by pady_1

1 answer

Consider the following statements A and B and identify the correct choice in the given answers : (A) Line spectra is due to atoms in gaseous state. (B) Band spectra is due to molecules

asked Dec 19, 2018 by pady_1

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Under minimum deviation condition in a prism, if a ray incident at an angle of $30^{\circ}$ . The angle between the emergent ray and the second refracting surface of the prism is :

asked Dec 19, 2018 by pady_1

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A short bar magnet with its north pole facing north forms a neutral point at $P$ in the horizontal plane. If the magnet is rotated by $90^{\circ}$ is the horizontal plane, the net magnetic induction at $P$ is : (Horizontal component of earth's magnetic field = $B_H$ )

asked Dec 19, 2018 by pady_1

0 answers

Two similar bar magnets $P$ and $Q$ each of magnetic moment $M$ are taken. If $P$ is cut along its axial line and $Q$ is cut along its equatorial line all the four pieces obtained have each of :

asked Dec 19, 2018 by pady_1

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There is no couple acting when two bar magnets are placed coaxially separated by a distance because :

asked Dec 19, 2018 by pady_1

0 answers

The pole strength of a $12\;cm$ long bar magnet is $2.0 \; Am$ . The magnetic induction at a point $10\;cm$ away from the centre of the magnet on the axial line is : $\begin{pmatrix} \frac{\mu_0}{4 \pi}= 10^{-7} Hm^{-1} \end{pmatrix}$

asked Dec 19, 2018 by pady_1

0 answers

Electric charges of $1\; \mu C, \; 1 \; \mu C$ and $2 \mu C$ are placed in air at the corners of $A, B$ and $C$ respectively of an equilateral triangle $ABC$ having the length of the side $10\;cm$ . The resultant forces at $C$ is : $\begin{pmatrix} \frac{1}{4 \pi \varepsilon_0} = 9 \times 10^9 \frac{N m^{2}}{C^2} \end{pmatrix}$

asked Dec 19, 2018 by pady_1

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A charged particle of mass $3 \times 10^{-6} kg$ is held stationary in space in an electric field of strength $10^6 NC^{-1}$ directed vertically downwards. The charge on the particle is : $(g = 10\; ms^{-2})$

asked Dec 19, 2018 by pady_1

1 answer

Two long parallel copper wires carrying currents in the opposite directions of 5 A each. If the wires are separated by a distance of $0.5\;m$ , then the force per unit length between the two wires is :

asked Dec 19, 2018 by pady_1

0 answers

For the following reaction in gaseous phase : $CO + \frac{1}{2}O_2 \to CO_2 \; \; \; \; K_c/K_p$ is :

asked Dec 11, 2018 by pady_1

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The shadow of a tower standing on a level ground is found to be 60 metres longer when the sun's altitude is $30^{\circ}$ than when it is $45^{\circ}$ . The height of the tower is :

asked Dec 11, 2018 by pady_1

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In a triangle $ABC, \;a^2 \sin 2C + c^2 \sin 2A$ is equal to :

asked Dec 11, 2018 by pady_1

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In a triangle $ABC, \; \frac{a}{b^2-c^2} + \frac{c}{b^2-a^2} = 0$ , then $B$ is equal to :

asked Dec 11, 2018 by pady_1

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In a triangle $ABC$ , $\frac{\cos C + \cos A}{c+a} + \frac{\cos B}{b}$ is equal to :

asked Dec 11, 2018 by pady_1

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$\sin^{-1} \begin{pmatrix}\frac{x}{\sqrt{1-x^2}} \end{pmatrix}$ is equal to :

asked Dec 11, 2018 by pady_1

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$\sec^2 (\tan^{-1}2) + \mathrm{cosec^2} (\cot^{-1} 3)$ is equal to :

asked Dec 11, 2018 by pady_1

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The equation $\sqrt{3}\sin x +\cos x = 4$ , has:

asked Dec 11, 2018 by pady_1

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If $A, B, C, D$ are angles of a cyclic quadrilateral, then $\cos A + \cos B + \cos C + \cos D$ is equal to :

asked Dec 11, 2018 by pady_1

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$\cos^2 ( \frac{\pi}{6} + \theta) - \sin^2 (\frac{\pi}{6} - \theta)$ is equal to :

asked Dec 11, 2018 by pady_1

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If $\mathrm{cosec} \theta = \frac{p+q}{p-q}$ , then $\cot (\frac{\pi}{4} + \frac{\theta}{2} )$ is equal to :

asked Dec 11, 2018 by pady_1

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$\frac{\sin 5 \theta}{\sin \theta}$ is equal to :

asked Dec 11, 2018 by pady_1

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If $\theta = \frac{\pi}{6}$ , then the $10^{th}$ term of $1 + (\cos \theta + i \sin \theta) +(\cos \theta + i \sin \theta)^2+(\cos \theta + i \sin \theta)^3 + ...$ is equal to :

asked Dec 11, 2018 by pady_1

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If $\begin{vmatrix} 1-i & i \\ 1+2i & -i \end{vmatrix} = x + iy$ , then $x$ is equal to :

asked Dec 11, 2018 by pady_1

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If $a$ is a complex number and $b$ is a real number, then the equation $\overline{a} + a + b =0$ represents a:

asked Dec 11, 2018 by pady_1

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If $A = \begin{bmatrix}0 & 2 \\ 3 & - 4 \end{bmatrix}, \; hA = \begin{bmatrix} 0 & 3a \\ 2b & 24 \end{bmatrix}$ , then the value of $h, \;a,\;b$ are respectively :

asked Dec 11, 2018 by pady_1

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A square matrix $[a_{ij}]$ in which $a_{ij} =0$ for $i \neq j$ and $a_{ij}=k$ (constant) for $i=j$ is called a:

asked Dec 11, 2018 by pady_1

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If $A = \begin{bmatrix} -2 & 2 \\ -3 & 2 \end{bmatrix}, \; B = \begin{bmatrix} 0 & -1 \\ 1 & 0 \end{bmatrix}$ , then $(B^{-1}A^{-1})^{-1}$ is equal to :

asked Dec 11, 2018 by pady_1

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The bi-quadratic equation, two of whose roots are $1+i, \; 1-\sqrt{2}$ , is :

asked Dec 11, 2018 by pady_1

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$\displaystyle\lim_{x \to 0} \frac{\sin x \sin^{-1} x}{x^2}$ is equal to :

asked Dec 11, 2018 by pady_1

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If $1$ is a multiple root of order 3 for the equation $x^4 - 2x^3 + 2x-1=0$ , then the other root is :

asked Dec 11, 2018 by pady_1

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The roots of the equation $x^3 - 14 x^2 + 56x -64=0$ are in :

asked Dec 11, 2018 by pady_1

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Each of the roots of the equation $x^3 - 6x^2 + 6x-5 =0$ are increased by $h$ . So that the new transformed equation does not contain $x^2$ term, then $h$ is equal to :

asked Dec 11, 2018 by pady_1

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$20^{2-3x^2} = (40\sqrt{5})^{3x^2-2}$ , then $x$ is equal to :

asked Dec 11, 2018 by pady_1

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